In 2007, John Dewar, the Rotorua CIB chief Ms Nicholas complained to, was jailed for 4 years for attempting to defeat the course of justice by covering up the allegations.
The commission of inquiry found urgent action was needed following the handling of rape complaints and the Office of the Auditor-General was tasked with monitoring the progress for 10 years.
Yesterday's half-way report said significant leadership challenges still existed within the police and most of the recommendations were still to be completed.
While levels of trust and confidence in the police were relatively high, the mixed progress in responding to the recommendations posed some risk to that trust and confidence.
"Effective implementation of the commission's recommendations is important for maintaining and improving the public's trust and confidence in the police," Deputy Auditor-General Phillippa Smith said.
She said the slow progress was, "relatively poor, given that it is five years since publication of the commission's report".
The report notes that access to specialist medical assistance for complainants in the South Canterbury District Health Board area needed to be improved as well as specialist training for police staff who might supervise, or be involved in, adult sexual assault investigations.
There also continued to be an "unacceptable" level of inappropriate sexual behaviour within the force, with some staff reluctant to report wrongdoing because of the way colleagues had been treated when they did.
"The necessary culture includes supporting people within the police to know what appropriate behaviour is, to understand what is expected of them, and to be willing to report observed behaviour that does not meet these expectations. It also includes being receptive to outside scrutiny, including complaints."
However, the report did say police had shown signs of improvement this year by giving greater priority to progressing the recommendations about adult sexual assault.
They had formed an adult sexual assault training review group, increased the number of districts with dedicated adult sexual assault teams, and revised adult sexual assault investigation guidelines.
Acting Police Commissioner Viv Rickard said police acknowledged they still had work to do. "We have made huge progress in some areas, particularly around the code of conduct, our disciplinary processes, and in reinforcing the standards of behaviour required by our staff."
Mr Rickard said police were making reasonable progress in most of the key areas and in some areas, especially around dealing with adult sexual assaults, the pace had accelerated considerably this year.
Police were confident the targets in the report would be met.
