South Island councils say the Government's new law on synthetic cannabis is weak and unworkable.
Councils have been chastised for being slow to use the Psychoactive Substances Act passed last year with the aim of determining where synthetic cannabis and other legal drugs can be sold.
The Hamilton City Council, which has brought in rules limiting drug sales to its central business district, had its powers confirmed on Wednesday but faces a judicial review in court.
A meeting of all South Island councils discussed the issue last week.
Dunedin mayor Dave Cull says the law was always a copout and now it's clear it is a mess, because councils have to define areas of sale but the Ministry of Health grants product licences separately.
Mr Cull says retailers and councils will each have to spend hundreds of thousands of dollars on court actions to clarify a poorly planned law. "Why should our retailers go to all that legal expense," he asks, "in order to plug holes in flawed legislation?'
Calling the legislation inept, Clutha mayor Bryan Cadogan says it has left a large loophole by shifting drug sales from corner dairies to people selling them door-to-door and not giving councils the power to stop it.
However, Associate Health Minister Peter Dunne says the law gives councils very strong powers for local plans to regulate drug sales. He says councils have a huge opportunity and he implores them to take their new powers up rather than sit on the sidelines sniping.