Wastewater samples have revealed the shocking extent of New Zealand's meth use.
A Massey University study looked at the prevalence of hard drugs in water treatment plants in Auckland and Australian cities, compared to European countries.
The study's author Professor Chris Wilkins says the results speak for themselves.
"The levels of methamphetamine found here in Oceania are significantly higher than in Europe and even most places in the United States," he said.
Meth levels in New Zealand were still found to be lower than most places in Australia though and there were less hard drugs.
Methamphetamine levels at both Auckland wastewater plants tested were lower than five out of the eight Australian plants tested.
"We have significantly lower levels of cocaine use and also lower levels of MDMA use," Prof Wilkins said.
No cocaine was found at any of the Auckland wastewater treatment plants, while MDMA was detected on only one day of the week.
In Australia cocaine and MDMA were detected every day at all eight treatment plants tested.