Former Associate Health Minister Peter Dunne has slammed a member's Bill proposing to increase penalties for dealing synthetic drugs, saying penalties simply will not solve the problem.

Numerous deaths, especially in the Auckland region, were attributed to deadly batches of synthetic drugs last year.

Pakuranga MP Simeon Brown's Bill, which would amend the Psychoactive Drugs Act 2013, would increase the penalty for dealing the substances from two years in prison to 8 years, and has passed its first reading.

National's Mr Brown wrote that "this Bill is necessary in order to protect our communities and young people from these harmful drugs, to deter those who are supplying them into the market, and to give Police stronger powers to crack down on suppliers".

Mr Dunne, speaking this morning with TVNZ 1's Breakfast called Mr Brown's Bill "naive nonsense" and put it down to being an "easy win" for him.

"It's been the easy one over the years - make the penalties tougher, hit those who are supplying," Mr Dunne said.

"There is a case for changing the penalties, because they are a bit out of line with the Misuse of Drugs Act, but to suggest that is the answer is simply naive nonsense."

Mr Dunne said synthetic drugs were under control in 2013, but parliament had backtracked due to "moral panic" from the public about the drugs.

"These drugs had actually been on the market for years - we'd brought them under control," he said.

"Parliament then backtracked and decided to change the law and the consequence of that, plus the unrelated but pretty important issue of a ban on animal testing of these substances, meant the law has been stymied for the last four years and the market's gone underground.

"Rather than dealing with that problem, we now have these silly little arguments around 'if we just toughen the penalties the problem will go away' - it won't work.

"The only way to get on top of it is to go back to what the Psychoactive Substances Act was all about - have products tested for the level of risk and sold properly through regulated stores."

Mr Dunne said increasing penalties would be popular with Mr Brown's constituents, but it would not solve the problem.

"The problem is, because this market is underground and is expanding, we've lost control of it.

"You end up saying 'well we've got to find out who these backyard producers are and penalise them hard' - it's a never-ending game we won't win ... I think our capacity to catch them is not that great.

"There's still this view that somehow the way to control these things ... is to prohibit and ban and limit things - all that does is make people go underground in what they do, and then you end up saying 'well that hasn't worked, we've got to prohibit more and ban more' and it becomes a never-ending circle and we've got to break out of that.

"There were some pretty big tragedies in Auckland last year and this is a local MP responding to that, I understand that ... its an easy win, it satisfies that legitimate concern, and I've got huge sympathies for families who were adversely affected ... but it doesn't resolve the fundamental problem."

Labour the the Green Party oppose the Bill, with Green MP Chloe Swarbrick saying last year in an interview with Stuff that the Bill will lead to "further criminalisation and all evidence shows it is just not going to work".

"Why are we wasting Parliament's time on doing this when the direction of travel for pretty much every jurisdiction that's been looking at updating their drug laws has moved towards one that focuses on health and on harm reduction," she said.

"The war on drugs has failed ... this has been proposed despite all evidence that the war on drugs has failed."