The Government pays about $5000 to test each product it suspects may be synthetic cannabis - a cost Associate Health Minister Peter Dunne says it is "prepared to bear".
"We currently have the Temporary Drug Class Notices regime which is focused on delivering safety first for young New Zealanders. This regime is specifically temporary."
Next year, a permanent law will be introduced which will require manufacturers to prove the safety of their products and pay for associated expenses.
On Saturday Enjoi Products released a repackaged and modified version of its Amsterdam Cafe synthetic cannabis to convenience stores across Auckland.
Managing director Zaid Musa said other firms were gearing up to re-release modified synthetic cannabis products. And the Herald understands at least one synthetic cannabis product, labelled "herbal tea", has been sold since the day after the bans in August.
Mr Dunne said officials checked out such "rumours" and acted on them if they were substantiated. "But the other [possibility] is we will find stuff that doesn't come within the ambit of what we're looking at."
The minister acknowledged it was possible at least one synthetic cannabis product would always be on sale until the Misuse of Drugs Act was overhauled next year.
Sixteen synthetic cannabinoids - the chemicals used in synthetic cannabis - were listed as the equivalent of Class C1 drugs at the beginning of August.
Mr Dunne said this week that three new synthetic cannabinoids had been banned. Packages of all three were found by Customs, and one was destined for Enjoi Products.
Yesterday, Ministry of Health officials spoke to Mr Musa and confirmed that Amsterdam Cafe contained a soon-to-be-banned cannabinoid. Mr Musa said Amsterdam Cafe was being recalled and would hopefully be off shelves by Wednesday.