CRITICISM: The way police respond to cannabis offences has been criticised by a former head of the National Drug Intelligence Bureau.

A recently retired senior police officer who once headed the National Drug Intelligence Bureau says police have made a "tactical mistake" in the way they deal with cannabis offences.

Detective Inspector Harry Quinn, who retired in 2008 after 37 years in the police, is calling on senior police to lead a debate on the cannabis issue, saying he is "disappointed" that no one in the organisation is prepared to speak out. He says this is because police see cannabis as a "political time bomb".

Quinn, who also helped set up the national organised crime unit and was involved in numerous cannabis eradication operations, says he took flak within police for writing a report recommending a relaxation of cannabis enforcement, which would have involved issuing warnings to adult social users.

A similar model has been suggested by the Law Commission, but the government has indicated it will not be changing drug laws.

Quinn's comments come after a recent hardline approach to cannabis, including the nationwide raids in April on hydroponic gardening stores.

In the latest edition of Norml News, the magazine of the National Organisation for the Reform of Marijuana Laws, member Stephen McIntyre says the April raids signal a "war on cannabis" by police and that previously there had been a degree of tolerance towards home cultivation for personal use. Law reformists say there is a perception from police that because the National government is tough on crime, they should clamp down on all areas of drug enforcement.

Elsewhere in the world, authorities are relaxing their attitude to marijuana, with US President Barack Obama saying medical users will not be pursued, and Californians are set to vote on measures to legalise the recreational use of cannabis.

Quinn told the Sunday Star-Times cannabis law did not need to be changed – but the way police enforced it did. They should rigorously prosecute anyone caught dealing drugs near schools or to youth, and anyone caught with cannabis in a vehicle, but go easy on adult recreational users, he said.

"If someone who is 40 years old is sharing a joint with their 42-year-old neighbour, they should simply tell them to put it out. Why we are wasting time prosecuting adults for the use of cannabis? I'm buggered if I know."

He said the Misuse of Drugs Act clearly differentiated between those dealing to young people and adult recreational users.

"Police ignored it completely and dealt with all offenders in the cannabis realm exactly the same. I think that was a tactical mistake."

He said there were worse drugs to worry about. "The big guns in the police should be pointed at the drugs which affect people's lives and can kill people – that's not cannabis."

Quinn said senior police needed to take another look at the law and issue guidelines to all officers "so it permeates all through.

"It's not a soft approach, it's just a different way of dealing with the problem."

But Detective Sergeant Paul Tricklebank, of the Drug Intelligence Bureau, said cannabis was harmful and a gateway to harder drugs. He said police did not pursue social users, only growers, dealers and gang suppliers.

tony.wall@star-times.co.nz