Detecting new drugs coming into New Zealand has been labelled as a "game of cat and mouse", according to the New Zealand Drug Detection Agency.
It follows an Environmental Science and Research report that shows more than 130 new psychoactive substances were detected at New Zealand's borders between 2014 and 2018.
Chief executive Kirk Hardy told Mike Hosking new drugs pose new risks in detecting them, which adds to the problem.
"If you look at the likes of Carfentanil...it's 10,000 times more potent than Morphine, it goes airborne and it's also transdermal. So if you touch it, you're going to get a dose and a potentially fatal dose, and if you open a bag of powder it can go airborne and you can overdose from that as well."
He said there has been an explosion in designer drugs recently, with the United Nations office of drugs reporting one new drug coming out per week.
Hardy said Chinese syndicates are behind a number of new drugs.
"One syndicate produced 16 tonnes of these chemicals per month."