Use of synthetic cannabis has fallen since it was banned but it's still easy to get on the black market, according to a new report on New Zealand's illegal drug scene.
The findings also show an increase in meth use and in the number of people buying and selling drugs online.
Massey University's just revealed its latest annual Illicit Drug Monitoring System study, which is based on interviews with more than 300 frequent illegal drug users.
It captures the 2014 drug scene and, for the first time, shows research evidence of the impact of the 'legal highs' ban in May of that year.
The study shows a sharp decline in the use of synthetic cannabinoids by ecstasy users, down from 22 percent in 2013 to six percent in 2014.
Massey University drug researcher and study co-author Dr Chris Wilkins says it shows the ban is working.
"We found significant declines in use, and also declines in availability and increases in prices, so it seems to be successful on a number of levels," he says.
But synthetic cannabis hasn't disappeared altogether -- 61 percent of those interviewed were able to purchase the drugs in one hour or less in 2014 (down from 91 percent in 2013), and more people are buying from gangs.
Synthetic cannabis also appears to have put a dent in the marijuana market, supporting recent claims of a "cannabis drought".
Frequent drug users said cannabis was less easily available and they also reported modest declines in use.
Dr Wilkins believes some cannabis growers may have turned away from it for good.
"I think a lot of criminal gangs have really latched on to synthetic cannabis as a much easier product to produce than growing cannabis, so I think it will be interesting to see whether the cannabis market actually recovers."
The surge in methamphetamine supply is continuing, particularly in Auckland and Christchurch. The proportion of frequent drug users who could purchase methamphetamine in one hour or less increased from 51 percent in 2011 to 76 percent in 2014.
The study's authors link the Christchurch increase to the city's rebuild and influx of young, male, construction workers.
"It is something that we need to keep an eye on. It is a cause of concern that we might be getting a new generation of meth use, certainly there's signs that the availability of meth is increasing in our part of the world," says Dr Wilkins.
And gangs are still playing a leading role in the drug market, with an increasing proportion of frequent drug users purchasing methamphetamine from a gang member -- up from 36 percent in 2013 to 50 percent in 2014.
However, the study also reveals more users are buying and selling drugs online.
"This is a real emerging trend where the impact of social media and encrypted websites are starting to influence how people obtain drugs or find out about drugs or see demonstrations of drug use," says Dr Wilkins.
"There's a new level of anonymity there, and there's also new access to drug types which are not traditionally available here in New Zealand."
He says that could turn out to be a real challenge for drug control in the future, but it could help reduce street crime.
"That [online sales] removes the need for street drug markets that might be places where there's violence, intimidation, robbery and things like that, and those transactions, if they happen online, that could potentially make a safer community."
The Illicit Drug Monitoring System (IDMS) has been conducted annually since 2006 and provides an annual 'snapshot' of drug use and drug markets in New Zealand.
The study interviewed 313 frequent drug users (109 frequent ecstasy users, 101 frequent methamphetamine users, and 103 frequent injecting drug users) from Auckland, Wellington and Christchurch.