Culturally important substances such as kava could be captured by a law change which aims to stamp out harmful synthetic drugs, MPs have told Parliament.
All eight political parties backed the Psychoactive Substances Bill at the first hurdle yesterday, though Opposition MPs hoped for clarification of the scope of the bill at select committee stage.
Labour MP for Mana Kris Faafoi said it was unclear whether the law would ban or limit the sale of kava crops, used in a traditional drink consumed at Pacific Island ceremonies and gatherings. Kava contained psychoactive substances and could have a sedative effect.
Mr Faafoi said: "There is a lot of cultural significance to kava and kava ceremonies ... for the Tongan community, for the Samoan community, and for the Fijian community. It is a serious issue."
He urged Polynesian communities to make submissions on the bill.
Psychoactive substances were defined broadly in the legislation as substances, mixtures, preparations, articles, devices, or things that were capable of inducing a psychoactive effect.
The law change put the onus on the industry to show that its products - such as party pills or synthetic cannabis - were "low-risk" before they could be sold.
Green Party health spokesman Kevin Hague argued that the threshold for banning substances needed to be well-defined.
"What does 'low risk' actually mean? If the threshold is set too high and no substances actually make it to market, what will occur then is that the existing situation will be perpetuated and the illegal trade in psychoactive substances will boom."
Associate Health Minister Peter Dunne said the bill was not designed to "ban absolutely everything forever". He said it was a pathway to a regulated market for psychoactive substances, if they could be proven to be safe.
The minister said the process of proving a drug's safety would require clinical safety trials, and would be expensive for the industry.
Opposition parties hoped for amendments at the select committee stage.
The Greens wanted Government to rule out the testing of party pills on animals. Mr Dunne has said there would be no lethal or barbaric tests on animals but said some testing on dogs would be difficult to avoid.
Labour welcomed the 18-year-old age restriction on buying and selling approved drugs, but suggested rules around packaging and advertising should also be written into the legislation.
MPs generally welcomed the ground-breaking legislation, with some hailing the new approach to drug use as a health issue instead of a criminal justice issue.
Mr Hague described it as New Zealand's first attempt to develop "rational, principles-based" policy with regard to drug-related harm.