Take another look at your humble corner dairy - it's on the frontier of a new world of designer drugs, and a telling symbol of how governments worldwide have been left scrambling to adapt.

New Zealanders can now pick up recreational drugs such as Kronic with their milk and bread, not because of liberal drug policy but because of a legislative loophole.

Although cannabis has long been illegal, the synthetic cannabinoid compounds that mimic its effects when smoked have - by the Government's own admission - caught it off guard.

Legally imported into New Zealand from countries such as China, the chemicals are dissolved and sprayed on to plant materials before being sold on to the public.

Synthetic cannabis has been made and sold in New Zealand for about 10 years, but the R18 products' use and sale were comparatively low-key until recently.

Chris Fowlie, co-owner of the Hemp Store in Central Auckland, said the long-term labelling of synthetic cannabis as "herbal incense" reflected the industry's initial caution.

"On one hand people could say that's not telling people the truth. Everyone knew they were for smoking. But by giving it another name it meant that it wasn't blatant."

But that approach changed when Lightyears Ahead, the company behind Kronic, realised there was no need to be coy, given the legality of its product, he said.

Shop-fronts were soon plastered with posters advertising Kronic, pre-rolled joints sold and synthetic cannabis adverts ran on mainstream radio stations such as The Edge.

"The result of that has been that it has annoyed a lot of people. It has been a little too blatant for a lot of people," Mr Fowlie said.

Associate Health Minister Peter Dunne counted himself as annoyed.

Media have labelled him "Dunne-nothing" after he opted against banning the products following a report by the Expert Advisory Committee on Drugs (EACD) in March.

With scientists still in the dark about the health effects of the products, Mr Dunne told the Herald at the time that any ban risked being overturned in court.

Instead, he enacted legislation to restrict the advertising and sale of the products. It's due to come into effect next month.

Mr Dunne has also vocally backed a Law Commission recommendation to make firms gain permission before selling synthetic drugs as a long-term solution.

The would-be seller would have to prove the drugs were safe. Such products can now be sold unless they are proven harmful.

The recommendation has near universal support - but because of legislative restrictions and November's election, the Government will not consider it until next year.

Until then, each news item on synthetic cannabis has left Mr Dunne fending off accusations of inaction.

That pressure came to a head early this month when screening by Environmental Science and Research (ESR) revealed two synthetic cannabis products illegally contained a prescription sedative.

Some critics say the Government should simply ban the drugs. Last week, eight of the most popular synthetic cannabis products were banned across Australia after action from the Federal Government.

Other countries such as the United States have also banned products outright. Mr Dunne said such moves weren't a solution as it "would work for five minutes until [Kronic maker] Matt Bowden's chemist comes up with his next concoction".

"We are dealing with a particularly dubious industry and there are many ways to get it wrong and you end up repenting at leisure.

"Fast law in this case would be bad law, and bad law results in loopholes wide enough to drive trucks full of Kronic through."

Dr Keith Bedford, general manager (forensic) at ESR, confirmed any cannabinoids placed on a banned list could be replaced by new versions.

"It's basically cat-and-mouse ... We're always just one step behind something that's been introduced."

Mr Fowlie agreed: "America banned theirs at the end of last year; the exact same brands are still available. They just reformulated them."

But Massey University senior researcher Chris Wilkins said stamping out versions of the legal highs was still worthwhile.

He suggested to the Law Commission that manufacturers should be made to prove the safety of their products, but he said other action could be taken in the meantime.

"They're always going to come back, but that's part of the battle. It's not going to be easy, but what's the alternative?"

Dr Wilkins said 49 per cent of men aged 20 to 24 had used BZP-based party pills in 2006, but since their ban, take-up of legal substitute versions had been minimal.

He said that while more research was needed to determine to what extent the ban led to more Ecstasy use, "it's just as plausible that people don't substitute between drugs, they just combine them".

Controlled drugs are normally listed by a specific chemical structure or name.

But New Zealand's analogue drug legislation allows for chemicals that are structurally similar to those controlled to be treated in the same manner.

Dr Wilkins said if the Government banned the 11 cannabinoids identified in ESR screening, manufacturers would at least be forced to find entirely new cannabinoids.

However, those in the industry such as Mr Fowlie maintain the emergence of designer drugs will force governments around the world to reassess what they call failed drug policies.

"These products would not be around if cannabis was legal ... and that shows if you ban these products, you're not going to get rid of the demand," Mr Fowlie said.

"Many of these cannabinoids have been developed specifically so they're not analogues of the other ones ... Theoretically there are thousands that could be developed."

This week, Mr Dunne announced in Parliament his intention to introduce urgent amendments to the Misuse of Drugs Amendment Bill by way of supplementary order paper.

He said the measures would clampdown on the "irresponsible" industry until the Law Commission recommendations could be adopted.

However, Mr Dunne has as yet refused to explain what the latest amendments will actually mean.

He has consistently hailed the Law Commission recommendations as a long-term solution to synthetic drugs, but their introduction could open another can of worms.

Mr Dunne, Prime Minister John Key, industry insiders such as Mr Bowden and Mr Fowlie and scientists such as Dr Bedford and Dr Wilkins have all backed the recommendation.

It's a diverse bunch that demonstrates how widely people's interpretations can differ on the "safety" threshold products like Kronic would have to meet.

Dr Bedford said that while the risks and benefits of products like paracetamol were evaluated before they could be sold, doing so for recreational drugs was more difficult.

He said while alcohol and tobacco were sold, if they were new substances being introduced into society they would likely fail a similar evaluation.