Methamphetamine charges hit 10-year high

The number of charges for the use and supply of methamphetamine is at a 10-year high.

Ministry of Justice statistics reveal there were more than 7000 charges in the past financial year and more than half were convicted.

Leading drug researcher at Massey University, Associate Professor Chris Wilkins, says enforcing drug laws alone won't solve the problem and we need a more health-based approach.

"Particularly for users, going through the criminal justice system often doesn't really address the underlying causes of their drug use," he told RadioLIVE.

"[We need] prevention and also drug treatment and making sure that drug treatment is available to people, including people in the regions where methamphetamine is often the biggest problem."

It comes after Prime Minister Jacinda Ardern refused to sign up to US President Donald Trump's new War on Drugs.

At least 124 countries have signed on to the President's 'Global Call to Action on the World Drug Problem', which Mr Trump is promoting at the UN this week, but New Zealand has said no.

Ms Ardern has said the war against methamphetamine has failed and agrees a health approach is needed.

"If we want to get to the issue, we actually have to look at what drives people's drug use in the first place," Ms Ardern told The AM Show in March.

"It's one thing to look at supply - dealing with people who are using solely through the criminal justice system hasn't worked. We do need to make sure we have proper services."