"The message need to be loud and clear that if they do not do the sentence then they can expect to go to jail," Judge Davis warned.
Lawyer Melissa Russell said Mahanga was prepared to do three days a week to try and reduce the hours of community work remaining and that had been arranged for Wednesday, Thursday and Friday. On average about eight hours are completed each day.
Mahanga's partner, who appeared in court, said she would assist in making sure he attended.
Judge Davis was honest in his response: "I've never heard such rubbish. You must think we are all stupid."
And his next course of action was also as succinct.
"You are going to do these hours otherwise you are going to jail."
Some quick math calculations were done and Judge Davis said by Mahanga's next appearance on October 14, 72 hours of community work had to be completed.
"If it's 71.5 hours done, jail, if it's 23 hours done, jail, if it's 73 hours done no jail.
"I don't think I can spell it out much clearer for you . . . I'm not mucking around. I will be the first to apologise too if these hours are done."
He released Mahanga but said a bail condition included being ready to go when the van called at his Paihia address to complete the first day of community work last Wednesday.Department of Corrections operations director Ali Rei said staff did all they could to motivate an offender to complete their hours.
"We have consistently held this person to account for his failure to engage with his court-imposed sentence of community work, and will continue to do so to uphold the integrity of the sentence," Rei said.
"As this matter is currently before the court we are not able to provide further specific information."
Mahanga was released on parole on February 6, 2016, after serving out a three-year jail sentence for the manslaughter of his partner 34-year-old mother of two Patricia Ann McGrath, also known as Wowo.
In June 2015, Mahanga was denied parole for the third time after the board discovered he had been taking methamphetamine in prison. He denied using meth intentionally and explained his drink bottle was spiked by former gang associates. However, he could not prove his claims and his security classification was increased to high.
Mahanga assaulted Patricia, after a 14-month relationship, in a house on Fairway Drive in Kamo in January 2013.
When 19-year-old Vitale Tufuga also appeared in Whangārei District Court last week having failed to turn up to the probation office on 51 occasions, with his last effort of eight hours on August 7, he was given clear instructions from the judge.
Judge Davis told Tufuga: "You are writing yourself a jail sentence."
He said the outstanding community work hours would need to be completed by October 8. Police opposed his bail and said he had a final bail warning on his record.
He was sentenced to 80 hours of community work and nine months' supervision after incidents in May 2018.
The Department of Corrections website said community work offenders did unpaid work in the community to pay something back for the offence they had committed.
"It also gives offenders an opportunity to take responsibility for their offending and learn new skills and work habits."
Offenders can be required to do between 40 and 400 hours of community work. The number of hours will be determined by the judge in court. While offenders will be encouraged to complete their hours as quickly as possible, they can only work up to 10 hours a day, or up to 40 hours in any one week.
Offenders must complete at least 100 hours every six months, or the remaining balance of their sentence.
While completing the hours, offenders would normally be able to continue with their regular jobs.
On the topic of holding offenders to account the website said non-compliance was treated very seriously.
It might mean an offender gets an internal sanction, for example a warning, a formal breach action which may result in a further conviction, another sentence, or imprisonment.
Or an application to the court to cancel the sentence and replace it with a more restrictive sentence could be made.