However, Wilkins said there was evidence of an emerging black market with more potency in the synthetic drug.
"The proportion reporting the strength of synthetic cannabinoids was 'high', increased from 14 per cent in 2014 to 59 per cent in 2015."
Meanwhile, there were reports of a "cannabis drought" in Christchurch and Wellington that was also driving up prices.
The proportion of frequent drug users who could purchase cannabis in one hour or less declined in Christchurch, down from 76 per cent in 2014 to 54 per cent in 2015, and in Wellington, down from 63 per cent in 2014 to 43 per cent in 2015.
As a result the price of an ounce of cannabis increased in Wellington, up from $279 in 2014 to $331 in 2015 and in Christchurch, up from $327 in 2014 to $353 in 2015.
Wilkins said this could be a reflection of the rise in supply of black market, synthetic cannabis.
"A recent study showed that 20 per cent of synthetic cannabinoid users reported reducing or stopping their natural cannabis use," he said.
Meanwhile the methamphetamine market remained healthy, with a growth of availability in Auckland and steady supply in the capital.
It was also being sold for cheaper prices, down to $668 in 2015 from $815 in 2011, through a gang, or gang-associate and in semi-public locations known as street drug markets.
Wilkins said the trends were indicative of a larger drug market offshore.
"Increasing availability of methamphetamine and declining prices is indicative of growing international methamphetamine supply in the Asia/Oceania region."
The study found that an increasing proportion of these drug users bought meth off a gang member or a gang associate - up from 30 per cent in 2009 to 54 per cent in 2015.
There was also a rise in the number of people who bought methamphetamine from a drug dealer - up from 63 per cent in 2014 to 80 per cent in 2015.
It also reflected the rise in street drug markets, up from 5 per cent in 2009 to 23 per cent in 2015 - though public areas, like a park, was the most frequent spot to get meth, up from 9 per cent in 2009 to 40 per cent in 2015.
Wilkins said this indicated there was a growing involvement of organised crime groups in the meth supply chain.
"This is another sign of a rising international supply of methamphetamine."
Online drug markets were also becoming an increasing place for drug users to get their fix, which Wilkins said were a place for people to "circumvent the traditional physical street markets and geographical barriers to supply".
Frequent drug users reported greater use of the internet to buy and sell drugs, including social media sites such as Facebook, Tinder and Snapchat and from encrypted websites.