It was described as default decriminalisation of all drug use, but a major law change last year about how police deal with drug users has had hardly any impact.
Nor does it appear to have made any difference to how Māori are disproportionately affected by the criminal justice system.
The lack of change has been met with shock by the Drug Foundation, which described what was a promising change as a complete failure.
But the Police Association says the data might show that police were already choosing not to charge many drug users - as long as that was their most serious offence.
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The Misuse of Drugs Amendment Bill, which brought about the change, codified police discretion that already existed but set in law that "a prosecution should not be brought unless it is required in the public interest".
In deciding whether to prosecute, police should consider whether a health referral for drug users would be "more beneficial to the public interest".
Green Party MP Chlöe Swarbrick, during the bill's third reading , called it "the most transformational change to our drug law in this country in over 30 years, because this bill will save lives".
Others, including Prime Minister Jacinda Ardern, said it simply codified current police practice - and that appears to be the case.
Roughly 2800 people have been brought to court for drug use/possession between mid-August 2019, when the law came into effect, and the end of March this year, according to police data released under the Official Information Act.
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During that time, police made 381 referrals to health services - or about 12 per cent of drug users that police encountered, not including those who were given formal warnings.
There is little difference in monthly prosecutions for drug use/possession before and after the law change, except for a small spike in prosecutions in April, May and June 2019, which is mainly due to charges for cannabis use.
Accounting for different levels of drug use throughout the year, the monthly prosecutions in January (354), February (298) and March (342) in 2020 are more or less the same as those months in 2019 (326, 284 and 364).
Almost all the charges are for cannabis or methamphetamine.
The new law also raised concerns about entrenching police bias against Māori , to which police responded by highlighting its programmes to counter unconscious bias.
An expert panel, whose work was internationally and nationally peer-reviewed, said last week that there was systemic bias in the system.
"Systemic racism in the justice system means that Māori are disproportionately more likely to be arrested, sentenced and convicted for drug offences, including cannabis-related crimes," the panel said .
The new data shows little change in the number of Māori brought before the courts for drug use/possession as a proportion of the total number of people.
It remains at about 40 per cent - both before and after the law change.
'Police need to explain'
Drug Foundation executive director Ross Bell said the law change, and the Government's push for a more health-based approach , had been a failure.
"I'm shocked there has been no change. 'Disappointment' is too polite a word. It seems the law was broken before it even began," Bell said.
"Our expectation was that most people who came into contact with the police for drug use offences would benefit from some kind of health intervention over a conviction.
"The police need to explain. What are the cases that wouldn't benefit more from a health intervention? Why is the conviction in the public interest?"
Bell said one of the aims of the new law was to shine a light on how police discretion operated so that its disproportionate application to Māori can be addressed.
"The fact there has been no change across the board and no change for Māori, makes me think we need to revisit the law change."
Police Association president Chris Cahill said he had expected prosecutions for drug users to have dropped more.
But he noted that there were often more serious charges accompanying a drug use/possession charge, which could mean that police were already choosing not to charge most drug users as long as they weren't committing more serious offences.
According to a Cabinet paper last year about the bill , there were 1351 people charged with drug use/possession as their most serious charge in 2017/18.
Applying the number of health referrals since the law change (about 50 a month) to that 2018/18 figure suggests that around 45 per cent of people are being referred to health services, if drug use/possession is their most serious offence.
Police Acting Assistant Commissioner Michael Johnson said the 381 health referrals since the law change were "very pleasing".
"But as with any change it will take time to fully embed the intent of the changes."
He appeared to say that health referrals were only being considered once an officer decided against prosecuting.
"The main change in an operational sense is that if an officer decides not to prosecute someone found to be using or possessing controlled drugs, they can now take an extra step and connect the person to health services."
Swarbrick said the data showed a "slight shift" in the right direction and she would continue to push governing partners for further reform.
"There are still a large proportion being brought before the courts to face a criminal conviction. We all know that culture does take time to change."
A proper review of the 45-year-old Misuse of Drugs Act was needed, she said.
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