Dozens of deaths and more than 1000 ambulance callouts in a year have left the Government facing what some say is an unprecedented synthetic cannabis problem.
"We would describe it as a public health emergency," New Zealand Drug Foundation executive director Ross Bell said.
"New Zealand has never experience this before and, in fact, no other country is experiencing [synthetic-cannabis-related] deaths at this level."
Like their counterparts in Australian states, New Zealand MPs have in the past decade wrestled with a response to the substances.
- Two deaths from suspected bad batch of synthetic drugs in Christchurch
- Christchurch Hospital's blunt warning to synthetics users after 7 admissions
Since their legal restriction, the products have moved underground and onto the black market, where their increasing potency and effects no longer resemble the marijuana high they originally tried to imitate.
The danger has become visible in the past year.
A coroner's report in June linked the drugs to as many as 45 deaths in a year compared with two deaths in the previous five years.
This is in a country that's evaded recent opioid crises and where the homicide count for 2017 was 48.
Ambulance staff say they have attended nearly 1200 call-outs related to synthetics in 2018.
Whether the relative surge was a matter of overzealous local producers applying too much chemical or a difference in alternative drug options compared with other countries was not clear, Mr Bell said.
But it was a bad batch - suspected of killing a man and putting 19 others in hospital - that this week prompted officials to consider raising two of the synthetic drugs to the same legal class as cocaine and heroin.
"That will give the police greater powers to go after the peddlers of these drugs and interrupt the supply of them into the community," Health Minister David Clark told reporters.
However, politicians and advocates across the political spectrum are sceptical about the proposal, given chemists can easily skirt restrictions.
Mr Bell said even if the move targeted sellers, it would catch users.
"The majority of them are homeless, living on the margins of society. The reason they use these drugs is to forget about the problems in their lives," he said.
The Green Party, a support partner of the governing coalition, has also reacted critically.
"We can choose to carry on with a failed war on drugs, or take a more sensible route and look at the causes and health impacts of addiction and treat those instead," Greens drug law reform spokesperson Chloe Swarbrick said.
The centre-right opposition National Party, meanwhile, has called for the Government to introduce harsher penalties for dealers of all synthetic cannabis.