Peter Dunne has revealed the government might have broken the law when they approved medicinal cannabis for a Nelson teenager two years ago.

This comes at the same time the associate health minister says he's feared for his and his family's safety while those wanting cannabis to be legalised have taken their anger with the country's laws out on him.

In 2015 Dunne gave ministerial sign-off to the family of Nelson teenager, Alex Renton, to import Elixinol from the United States.

CHRIS SKELTON/FAIRFAX NZ Associate health minister Peter Dunne says supporters of cannabis legalisation "hijacked" the medicinal cannabis debate.

While there's a loophole in New Zealand's law that allows people to bring back 30 days worth of a prescribed drug from overseas - the law only applies to those drugs approved under federal, not state law, because border control is covered by federal law.

Elixinol isn't legal under federal law, so while Kiwis can pick up a prescription in places such as Colorado and California, taking it out of the country is illegal.

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FACEBOOK Nelson teenager Alex Renton was the first Kiwi to be treated with imported medicinal cannabis. He died in July, 2015.

"It raises the possibility, and I can't say this absolutely, but I suspect on that basis that what we did in the Renton case was probably illegal, because he sourced Elixinol out of the US," Dunne said.

The hate mail, abuse and threats all started when Dunne approved medicinal cannabis for Renton - he was the first person in New Zealand to be granted import permits by the minister.

Renton was in Wellington Hospital at the time with "status epilepticus" a kind of prolonged seizure and died on July 1, 2015 - less than a month after receiving his first does of the cannabidiol oil.

"There have been a lot of genuinely concerned people from the perspective of trying to gain access to a medicine that they see will help them. I have no criticism of them, almost deep respect for them. But I think the argument was hijacked by people who saw this as part of another campaign - the recreational use thing - the 'just let us grow the weed' argument.

"The more I focused on the medicinal side, I think, the more strident they became," he said.

"I actually don't think any of those people were genuinely concerned about the people who were suffering, they were thinking about their own selfish agendas."

Every time the media reported something Dunne said the attacks on him would kick off, which have even led to him getting restraining orders against several people.

Police have been in almost constant contact with him as he's experienced everything from abusive messages in chalk written outside his family home to being abused in the street and protesters with loud hailers outside his front door.

All because Dunne has been the final point of sign-off for Kiwis wanting access to medicinal cannabis.

Dunne hasn't turned down a single application he's received from the MInistry of Health but under a loosening of the laws last week the buck will now stop with the ministry who will have ultimate sign-off.

"I've had every abusive email you can imagine from every strange creature equally imaginable."

"I've never had that level of intense anger and this has been going on now for about two years."

Dunne said he'd find notices on Facebook telling people to turn up at his home to protest.

"My wife goes home each night from work long before I do so she was often coming home to their handiwork. It's pretty unsettling and disturbing.

"I made the decision very early on in the piece that this was likely to be a continuing feature and I just had to shut it all out. And this might have contributed to a persona of arrogance but I remained deliberately aloof from all of it and the individual cases and the noise around them.

Dunne's hopeful that relinquishing sign-off for medicinal cannabis will put an end to the attacks he's been on the receiving end of.

"Hopefully it might be a game-changer but I don't think it will but I'm happy to be proven wrong."