The Prime Minister is standing by her claim today that synthetic cannabis is being laced with fly spray, despite experts dismissing it as a myth.
It's believed up to 50 people have died after using the drug and the Government is developing an action plan to respond.
During an interview on the subject today, Jacinda Ardern told TVNZ1's Breakfast show: "There are products being sold that are harmful in some cases, of course, you’ve got fly spray on some products."
However, the Government was told by the Ministry of Health in August this isn't true.
"There is no evidence to suggest that household chemicals, such as fly spray or weed killer are routinely used in the production of synthetic cannabis. This is a pervasive myth that has been repeated by police officers, people using the drug and sometimes suppliers.
"However, testing of samples by ESR does not return positive results for these chemicals," the Ministry of Health said.
In July Police Minister Stuart Nash publicly apologised for saying "fly spray and grass clippings" were killing people.
"I accept I should have been more considered in my comments and you are right… 'fly spray and grass clippings' are not killing people.
"I do know the issues and police and health are working on solutions. Apologies for appearing flippant on a very serious issue," Minister Nash said on Twitter.
Asked for an explanation for this morning's comment, a spokesperson for the Prime Minister responded:
"The Government has received advice from police that household chemicals, including fly spray have been used in the production of synthetics."
The Prime Minister’s office would not release the advice to 1 NEWS today.
ESR's forensic chemistry manager Kevan Walsh recently told 1 NEWS, "there's really no basis for those stories that are going around" when it came to the claims synthetic cannabis is being laced with fly spray.
"We have no evidence that there is any sort of significant application of those chemicals."
The police have previously admitted they have no evidence to support the claim.
"Police have been told anecdotally that some strands of synthetic cannabis could contain weed killer or fly spray, however, we have no evidence whatsoever of this being the truth," the police told NZ Herald last year.