Methamphetamine is becoming cheaper and easier to find, a Massey University study shows.
The rise in the availability of meth comes as availability of other drugs used recreationally falls and black-market synthetic cannabinoids emerge.
Findings from the latest Massey University Illicit Drug Monitoring System (IDMS) showed the change occurring between 2015 and 2016.
Several frequent drug users reported meth was easier to obtain, increasing from 19 per cent in 2015 to 44 per cent in 2016.
The average price of the product had also dropped in two city centres.
"The average price of a gram of methamphetamine declined in Auckland from $579 in 2015 to $485 in 2016, and in Christchurch from $1002 in 2015 to $746 in 2016."
The weight of meth seized had increased from 99kg in 2014 to 941kg in 2016.
The IDMS study provides an annual snapshot of trends in illegal drug use and drug markets in New Zealand.
Massey University associate professor and lead researcher Chris Wilkins said frequent drug users also reported a sharp rise in the availability of crystal methamphetamine – the imported form of meth.
"The proportion of frequent drug users who reported crystal methamphetamine was 'easier' to obtain more than doubled, increasing from 17 per cent in 2015 to 35 per cent in 2016," Wilkins said.
"The proportion of methamphetamine users who reported using crystal methamphetamine also showed a sharp increase, from 54 per cent in 2015 to 76 per cent in 2016."
The drug users also reported a decline in the availability of cannabis and ecstasy.
The proportion of frequent drug users saying ecstasy was "more difficult" to obtain increased from 9 per cent in 2015 to 24 per cent in 2016.
However there were some reports the strength of the drug had increased in recent years.
"The price of ecstasy remains low. The average price per pill has steadily declined from $59 in 2006 to $41 in 2016.
"Fifteen per cent of the people who purchased ecstasy reported purchasing it from the internet in 2016."
There was also a sharp decline in the availability of cannabis from 2015 to 2016, following the trend after a number of years of steadily declining availability.
Drug users reporting that cannabis was "more difficult" to obtain increased from 17 per cent in 2015 to 34 per cent in 2016.
The decline in cannabis availability occurred in all the main centres, Wilkins said.
"The proportion of frequent drug users who could purchase cannabis in one hour or less has declined from 82 per cent in 2014 to 54 per cent in 2016.
"Consistent with this decline in availability, there has been some decrease in cannabis use."
The availability of synthetic cannabinoids decreased from 2013 to 2016, with sharp declines reported after bans imposed in 2014.
However, the strength of synthetic cannabinoids increased from 2014 to 2016, reflecting the emergence of a new wave of high-potency synthetic cannabinoids.
"Consistent with the subsequent emergence of a black market for synthetic cannabinoids, there were sharp increases in the proportion of frequent drug users who purchased synthetic cannabinoids from a 'tinny house' – up from 2 per cent in 2013 to 53 per cent in 2016, the 'street drug market' – up from zero per cent in 2013 to 30 per cent in 2016, and from the 'internet' – up from zero per cent in 2014 to 35 per cent in 2016."
The Illicit Drug Monitoring System (IDMS) provides an annual "snapshot" of drug use, drug markets and emerging drug use in New Zealand. A total of 310 frequent drug users were interviewed for the 2016 study.
This included 133 frequent methamphetamine users, 111 frequent injecting drug users and 66 frequent ecstasy users from Auckland, Wellington and Christchurch, from October 2016 to February 2017.