NZ cannabis stronger than ever - study

Police are worried by the results of a study which has found the potency of cannabis being grown in New Zealand is stronger than ever before.

The secret police study involving scientists from Environmental Science and Research (ESR) using sophisticated hydroponic equipment to complete three cannabis growing cycles found that the drug was now more than four times stronger than it was when ESR last tested it in 1996.

The THC level - the primary intoxicant - varied between 4.35 per cent and 25.3 per cent during the study completed under Ministry of Health licence between 2004 and 2006, the Sunday News reported.

When ESR last tested the Class C drug, they found an average THC level of just 6 per cent.

The results of the study confirmed police suspicions that the drug was getting stronger as a result of criminals using more sophisticated growing methods, helped by the availability of specialised equipment, like that sold at hydroponic specialist shops.

"We've been aware through various techniques and our information that THC level has been increasing, and this study confirms it,"

said Detective Inspector Stuart Mills, chief of the National Drug Intelligence Bureau.

More than 250 people were arrested on more than 750 charges last week as police busted the Switched on Gardener chain of stores and large-scale cannabis-growing enterprises allegedly linked to the business, and other similar companies.

Scientists undertaking the research grew the drugs in a room "comparable to the average New Zealand bedroom, which is a space commonly used to grow cannabis indoors", according to the ESR report.

"It's a serious drug. And it's very clear that long-term usage has very long-term effects ... it's not the social drug of the 60s any more ... it is a drug that causes serious harm," Mr Mills said.

The report said the cannabis information was needed to assist in the court process, "when they are considering the severity of the offending, and in particular how much income is being derived from such an illegal operation".

- NZPA