Under the contracts with government agency Crown Law, they are supposed to hire staff reflecting the diversity of their regions and also demonstrate their commitment to the Treaty of Waitangi.
While all the Crown prosecution firms RNZ spoke to were incorporating te reo Māori and tikanga in their work - some said there could be a conflict between Treaty obligations and equality before the law.
One Crown Solicitor said while Māori were overrepresented in prosecutions, they were also more likely to be victims of crime. Where reduced sentences were granted on the basis of cultural factors that could sometimes leave Māori victims feeling short changed.
Despite stipulating in its contracts that private law firms should try to reflect the diversity of their regions, Crown Law doesn't collect ethnicity data on Crown Solicitors or the dozens of Crown prosecutors working under them.
As private companies they are not subject to the Official Information Act but RNZ asked the law firms how they were meeting their obligations to diversity and the Treaty and 11 of the 16 responded.
In Gisborne, where 53 per cent of the population is Māori, all the nine Crown prosecutors at Elvidge & Partners are Pākehā, including the Crown Solicitor Steve Manning.
"We are competing for the small number of Māori law graduates with the big city firms, government departments and other Crown offices," Manning said.
The firm's last Māori prosecutor left the firm four years ago and is now a partner in another Crown firm.
"We are very conscious of the need to try to attract suitably qualified Māori prosecutors but are going to have to show more ingenuity in doing so."
In Christchurch, where Raymond Donnelly has held the Crown warrant since 1914, there are no Māori Crown prosecutors.
Crown Solicitor Mark Zarifeh, who is of Palestinian and New Zealand European heritage, said the firm had 19 other lawyers, 18 of whom are European New Zealanders.
Whanganui also has no Māori on its team of six Crown prosecutors.
Crown Solicitor firms in New Plymouth, Palmerston North, Dunedin and Tauranga each had just one prosecutor with Māori heritage.
The makeup of Hamilton's Crown solicitor firm, Hamilton Legal, is more diverse. The 11 prosecutors include one Samoan and two Māori prosecutors, plus a Māori law graduate who will soon become a junior prosecutor.
The two largest Crown firms, covering the warrants for Auckland City and Manukau, also appear to be reflecting the diversity of their regions.
Meredith Connell, which has held the Auckland warrant since 1921, said of the 35 lawyers in its Crown specialist group 17 per cent identify as Māori, 11 per cent as Asian and 9 per cent as Pasifika.
In Manukau, Kayes Fletcher Walker has 39 lawyers - 24 are Pākehā, six are Māori and four are Pasifika. The firm also has prosecutors from China, Sri Lanka, Iraq, the Democratic Republic of the Congo and Macedonia.
Manukau Crown Solicitor Natalie Walker said the firm actively sought out Māori lawyers, including through a programme where Māori law students were paid and supported to work with the firm for up to three months.
Luke Cunningham Clere, which has held the Crown warrant for Wellington since 1936, didn't give specifics but said its prosecutors were of Māori, European, Pasifika and Lebanese heritage.
Crown Solicitors for the Invercargill, Tasman, Timaru, Rotorua and Whangārei regions did not respond to RNZ's inquiries.
Under their contracts with Crown Law, the firms are also supposed to show commitment to the "values and principles" of the Treaty.
All 11 firms who responded to RNZ said they were trying hard to do so, mainly by using te reo Māori and tikanga in their work and by offering scholarships and incentives to Māori law students.
But when culture was used in the administration of justice some said it could cause tensions.
Manukau Crown Solicitor Natalie Walker said her prosecutors at Kayes Fletcher Walker were often involved in Te Pae Oranga, an iwi-led, restorative justice approach.
Walker said it provided a "principled alternative to prosecution that still holds offenders to account and enables them to put right the harm" caused by their offending.
"If a defendant successfully completes the Te Pae Oranga process our lawyers reassess the public interest in the prosecution under the Solicitor-General's guidelines."
The prosecutors could then respond by offering no evidence - "in other words we choose to discontinue the case, judging that it is no longer in the public interest to do so".
But Whanganui Crown Solicitor Michele Wilkinson-Smith said when taking cultural factors into account it had to be acknowledged that Māori were more likely to be victims of crime too.
"The concepts of partnership and equality before the law are very familiar but on a day to day basis faced with Māori offenders and Māori victims, I think that there is a tension between honouring the principle of partnership and providing equality before the law."
She said one example was the use of cultural reports where, under Section 27 of the Sentencing Act 2002, offenders can outline cultural factors which may have contributed to their offending.
"It is very important that we do not overlook the fact that many victims of crime are Māori and they are guaranteed the rights and protections of the law," Wilkinson-Smith said.
"They are often very upset by the discounts provided for cultural factors. Victims of crime, particularly female victims of crime, often suffer from an imbalance of power. Focus on rehabilitation of the offender can exacerbate their feelings of worthlessness. They may feel pressured to agree to meet the offender or support a rehabilitative outcome."
The responses RNZ received showed that diversity and Treaty obligations are sensitive topics for Crown Solicitors.
"I have held a concern for a long time that we don't have a criminal bar - Crown and defence - which reflects the diversity of our community," Tauranga Crown Solicitor Anna Pollett said.
Pollett Legal, whose warrant covers the area from Waihi down to Te Kaha on the East Coast and inland to Kawerau, has run an internship for Māori law students and had mixed results in attracting talent.
"I am hopeful that in time we will have legal representation that more accurately reflects our community."
But Cherie Clarke, Crown Solicitor for New Plymouth, said "mere statistics will not necessarily show the true diversity" of the Crown solicitors' network.
"For instance you ask for my details which merely are NZ European, female, aged 51," she said. "What they do not tell you is that I am from a working class family who grew up in Christchurch."
She said she was raised in a state house in Momorangi Crescent in Redwood - "my parents would not let us kids walk down one side of the crescent because they considered it too dangerous" - and her father worked three jobs to build a modest, three-bedroom house.
"There is more to my bio than that but you should know that if my statistics are used to suggest I am from a white privileged background I will be very upset," she said. "I am very proud of where I have come from."
Other Crown Solicitors accept that they shoulder some responsibility as major players in a justice system where more than 50 per cent of the men in jail, and more than 60 per cent of the women, are Māori.
Brian Dickey, one of the few Māori Crown Solicitors, said his firm Meredith Connell worked on the basis that the Crown had not honoured the Treaty.
"The way the criminal justice system has operated has been disproportionately adverse to Māori, and our firm, as office of the Crown Solicitor at Auckland, shares responsibility with successive governments over the decades."
Meredith Connell aims to have 20 per cent of its Crown prosecutors reach a conversational level of te reo Māori by 2023 and also runs programmes encouraging Māori school and university students into the law.
Dickey said the relationship with mana whenua had historically been strained.
"However, at a pace which is comfortable for both sides, we hope our relationship will evolve positively over the years ahead and I hope that will be the main legacy I leave."
This story is part of the series Is This Justice?
