Pākehā are nearly twice as likely to be let off by police for minor offences than Māori, a new report by the Independent Police Conduct Authority has shown.
Figures between February and April 2015 showed 40 percent of New Zealand European offenders were given a pre-charge warning in Northland, compared to 25 percent of Māori.
In the Waikato, 55 percent of Pākehā were let off, compared to 24 percent of Māori.
An offender can get a pre-charge warning if they commit a crime with a penalty of less than six months imprisonment, such as trespassing or cannabis use.
The report said between April 2015 and early 2016, the Police National Headquarters alerted districts to work at reducing the disparity between New Zealand Europeans and Māori offenders.
It said the difference in warnings issued was reduced over that period of time, but still persisted in some parts.
In April this year, 46 percent of Pākehā offenders were let off with formal warnings in Northland, while only 22 percent of Māori were given one. Other areas like Waikato, Counties Manukau and Canterbury showed similar patterns.
But the IPCA said, despite this, there was no evidence of racial bias.
General manager Warren Young said the criminal backgrounds of offenders played a part in whether police officers decided to charge them for minor crimes.
"Eligible Māori offenders are much more likely to have previous criminal convictions when they have committed an eligible offence, therefore it would be expected that they would be less likely to receive a pre-charge warning."
He said the evidence backed that up. Of those who received a formal warning, 51 percent of non-Māori had no prior criminal convictions, compared to 26 percent of Māori.
He said the difference between the two groups did still warrant a call by the IPCA for more guidance as to how police made decisions when issuing warnings.