Today's report looked at the whether or not the initial police criminal investigations were adequate.
It also looked at the handling of any complaints or reports received by police from members of the public between 2011 and October 2013.
Independent Police Conduct Authority chair Judge David Carruthers said the authority investigated whether there was any police misconduct or any failure of police practice, policy or procedure in the handling of seven separate reports made to them in relation to the Roast Busters.
In its report, the authority found that investigating staff treated young women who were subject to alleged offending with "courtesy and compassion".
However, Judge Carruthers said the authority found investigations into original cases were not "robust and thorough".
"In a number of cases police failed to adhere to the basic tenets of any form of criminal investigation."
Judge Carruthers also said police failed to undertake adequate follow up enquiries and pursue positive lines of enquiry.
He said there was also a lack of record keeping and assessment of evidence during investigations.
The report also found that officers investigating the matters tended to approach each case on a "case by case" basis to consider whether there was sufficient evidence to prosecute offenders for sexual violation.
Mr Carruthers said in the authority's view, the officers should have identified connections between the various cases.
"Victims were let down by their failure to do so," Judge Carruthers said.
Judge Carruthers said details of alleged offenders were not correctly recorded in the police computer system.
"Moreover, police did not check whether the young men had been involved in any previous incidents."
The authority's report also criticised investigating officers for failing to properly consider alternative action, and take steps to address care and protection issues and the potential offending behaviours of the young men involved.
Judge Carruthers said only one of the young men was ever the subject of a referral to Child Youth and Family. "In one case, initial suspect interviews were held with the young men, but there was no further contact after that.
"In the other cases, officers did not speak to the young men or their parents during or at the conclusion of their investigations," Judge Carruthers said.
He said the officers' contact and interaction with young men who were the subjects of the investigations and their families was "inadequate or non-existent".
Police need to do 'whatever possible'
Police Commissioner Mike Bush has apologised "unreservedly" and says police will reach out to complainants in the Roast Busters case immediately.
Mr Bush said he completely accepted the IPCA findings and police officers need to do "whatever possible" to stop a repeat of the kind of sexual conduct that outraged New Zealand when the scandal broke.
He did not believe the reprimanded officers would or should be sacked.
"They were well-trained. It was a lapse in performance at this point in time."
Mr Bush maintained Operation Clover was a "comprehensive" investigation.
"I'm very disappointed," Mr Bush added.
However, he said staff failures were isolated incidents and the officers criticised in the IPCA report were no longer on the child protection or sexual assault investigation teams.
Mr Bush confirmed Waitemata area commander Bill Searle would conduct a performance appraisal to determine where "accountability sits" in relation to police failures.
"Remedial actions will help prevent such situations arising again," Mr Bush said.
Extremely disappointing failures
On his way to question time today, Police Minister Michael Woodhouse was asked how anyone making a complaint of sexual assault could be expected to be taken seriously, given the report's findings.
"It clearly shows some failures on behalf of individual police who were charged with investigating, and that is extremely disappointing," Mr Woodhouse said.
"I have received an assurance from Commissioner Bush that the steps that are required to be taken to ensure that this doesn't happen again are being taken, and I will continue to monitor those reports."
In 2007 a report by Dame Margaret Bazley identified systemic issues and behavioural patterns within the police, and made 60 recommendations for change over a 10-year timeframe.
Mr Woodhouse said he had to question whether the Roast Busters case represented a failure of that action, or an isolated incident that is "a disappointing exception to a general trend of improvement in police".
"I am satisfied that it is the latter," Mr Woodhouse said. "Police dropped the ball by failing to join the dots? It is a case of individual failure, rather than systemic failure."
Dealing with the police officers who had failed was a matter for police, Mr Woodhouse said.
Report 'sober reading'
Jacinda Ardern, justice spokeswoman for Labour, said the IPCA report was damning and "sober reading".
"The IPCA have demonstrated what I believe the public has instinctively felt for a long time - that far more should have been done to intervene and to prevent further harm being done.
"Instead, mistakes were made, complaints weren't properly investigated, and the police had very little contact with the alleged offenders or their families."
She said the fact that the Child Protection Team staff did not evaluate all available offences and options to prosecute was the most damning finding.
"Quite simply, there were options to prosecute that weren't explored, let alone discussed with the victims."
"This report makes for sober reading," Ms Ardern said.
"Yes, there were attempts to do the right thing by the victims, but the failure to properly intervene at the start made victims of more young women down the track."
In November 2013, videos emerged of the group that allegedly showed them laughing and bragging about having sex with drunk and underage girls.
At the time police said there was nothing they could do until a formal complaint was made.
It was later revealed that police had been approached by young girls with complaints in 2011 - police later confirmed this was true.
Following this, the Police Minister announced the IPCA had been asked to investigate.
The investigation was re-opened and police child sexual abuse specialist Detective Inspector Karyn Malthus was appointed to head the investigation, named Operation Clover.
In 2014 police released their findings into Operation Clover and announced no-one from the group would be charged because of insufficient evidence.
Today's report refers only to police's initial investigation, and does not include the Operation Clover re-investigation.
'We clearly let the victims down'
District commander for Waitemata Superintendent Bill Searle has publicly apologised to the young women and their families at the centre of the investigation into the Roast Busters group.
"I'd like to publicly apologise to the young women and their families for the trauma that has been caused to them. I will arrange to do this in person, depending on their wishes," Mr Searle said.
"I accept the IPCA's findings that some of my staff did not meet the required investigation standard and did not connect the various cases or work with other agencies to develop preventive strategies.
"They also missed opportunities to communicate with the parents of the young men.
"We clearly let the victims down."
He said he reassured the public that police were committed to making sure this doesn't happen again.
Mr Searle said the IPCA has accepted the incidents involving the Roast Busters group presented police a complex set of challenges and investigators were highly motivated to do the right thing by the young women concerned.
Sexual violence campaigner Louise Nicholas said she believed the Police had learnt the right lessons from the Roast Busters case.
"It's encouraging to know that the police are taking that extremely seriously and will effect change. I know for sure that is happening now," she said.
Mrs Nicholas has been involved in training crime managers for the past two years after police realised that they had not "connected the dots" between the various complaints from the Roastbusters' victims.
"If that had been happening back then, I'm quite sure those dots would have been connected," she said.
"Hand on heart, I believe it can't happen [again] because of the systems that are now in place."
However, Rape Prevention Education director Dr Kim McGregor said police were still not contacting specialist support agencies every time they received a complaint of sexual assault.
"We know that there are pockets of poor practice around the country. There are also pockets of excellence," she said.
Dr McGregor and Mrs Nicholas met Justice Minister Amy Adams yesterday to seek funding for advocates in specialist agencies to support sexual assault victims all the way from their initial complaint until after any subsequent court case, as recommended by the Law Commission.
Mrs Adams announced recently that she had asked the commission to resume its work on reviewing the way sexual abuse cases are handled, and Dr McGregor said the minister was "very open" to funding independent advocates.
"In this Roast Busters case the independent advocates were not alongside those families. If they were, maybe they would have been monitoring what have the police done about it," she said.
"Our specialist agencies have been under-funded for so many decades, so every time the police call us we need to be able to respond. If resourcing is an issue, we need to be able to fix it."
An independent taskforce
The Green Party is calling on the Minister of Police to immediately establish an independent taskforce to implement and enforce changes in police culture.
Women's spokeswoman for the Greens Jan Logie said the Police Minister must take action.
"The Police Minister must immediately establish a taskforce to implement the recommendations in this report, the 2007 Bazely report and the 2010 IPCA report, and to enforce a significant culture shift in polices attitudes towards the victims of child abuse and sexual violence.
"This is the third review highlighting the same problems, a fact that the IPCA found 'disturbing'," Ms Logie said.
"Revelations that the Police could have stopped the so called Roastbusters from preying on young women but didn't even bother talking to the young men, or their parents, defy belief."
Ms Logie said it was hard to conceive how the police could do right by the complainants now, but that the Police Minister could ensure that failures like this never happen again.
Green Party co-leader Metiria Turei said she was "shocked" by the IPCA revelation, that police may have stopped the Roast Busters from "preying on young women" but they did not even bother to talk to the young men or their parents.
"Police claims that they didn't have enough evidence to prosecute the men can't be taken seriously when they never fully investigated the cases in the first place."
She said New Zealand's public needed confidence that "practical changes" would be made.
"Police are not investigating these complaints properly, they are not keeping complaints of these records properly, and more and more young people are at risk as a result - that is what the IPCA report shows very clearly."
She said it was a serious criminal matter involving young people who were in need of real help.
"The police failed to play their role in this. We need to make sure every New Zealander can go to the police, make a complaint and have it taken seriously."
Dr Kim McGregor of Rape Prevention Education said she supported Ms Logie's call for a taskforce to oversee and implement the recommendations of the IPCA's findings and change police culture.
"What we want to do is encourage the police to move on those areas where they know there are poor practice and often we think it comes from the top," Dr McGregor said.
She said there were "pockets of excellence" within police around the country, but she'd like to see some police managers "weeded out".
"Particularly managers that have a poor attitude towards young women who are reporting sexual violence," she said.
She said police should be enlisting the assistance of specialist sexual assault agencies such as Rape Crisis and Auckland Help in every case involving sexual assault, and in some cases Dr McGregor knew police didn't call them in.
She said she wanted to see changes made from the top of the Waitemata Police District.
"Let's look at the top," she said.
Timeline
• 2011: 15-year-old victim lays complaint with police about the group's alleged activities.
• 2011: Green Bay High School counsellor claims she went to senior management to raise concerns about alleged Roast Buster Beraiah Hales.
• November 21, 2013: 111,000-strong petition demanding stronger action over the scandal delivered to Parliament.
• April 2012: Green Bay High School receive allegations about Hales.
• May 2012: Hales leaves Green Bay High School.
• November 3, 2013: Videos emerge of a group of boys calling themselves the Roast Busters showing them laughing and bragging about having sex with drunk and underage girls. Detective Inspector Bruce Scott said even though police were aware of the group, there was nothing they could do until a girl was "brave enough" to make a formal complaint.
• November 5, 2013: Superintendent Bill Searle said none of the girls from the original inquiry wanted to make a formal complaint.
• November 6, 2013: A 15-year-old girl comes forward to say she laid a formal complaint with police in 2011 -- when she was 13. Police later confirm this is true.
• November 7, 2013: After calls for action, Police Minister Anne Tolley announces she has asked the Independent Police Conduct Authority to investigate.
• November 12, 2013: Police child sexual abuse specialist Detective Inspector Karyn Malthus appointed to head the newly named Operation Clover.
• November 16, 2013: Nationwide protests take place, with hundreds calling for an end to the country's 'rape culture'.
• November 17, 2013: A girl who says she made a complaint to police two years ago reveals she has made a second complaint after the Roast Busters scandal.
• November 21, 2013: A petition is presented to MPs outside Parliament with more than 110,000 signatures calling for more action for the alleged victims of the Roast Busters.
• December 12, 2013: Then Police Commissioner Peter Marshall grilled by a select committee in Wellington about the police response to the case.
• May 22, 2014: The Independent Police Authority releases its first report into the initial investigation, which focused on information provided by police to media, which said a "systemic breakdown in communication" by police led to inaccurate information being provided to the public, however, said "no individual could be criticised" for that.
• October 29, 2014: Police release the findings of Operation Clover and announce no prosecutions will be made.
• March 19, 2015: The Independent Police Authority releases a report criticising police handling of the initial investigation.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (4pm to 6pm weekdays)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• The Word
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• CASPER Suicide Prevention
If it is an emergency and you feel like you or someone else is at risk, call 111.
