Synthetic drugs linked to the deaths of 11 people in two months contain a notoriously dangerous chemical manufactured overseas.
Police have confirmed AMB-FUBINACA has been found in synthetic drugs tested by the Environmental Science and Research Crown Institute (ESR).
A forensic chemist at ESR, Kevan Walsh, said it tested samples taken from drugs linked to people who have died, as well as from police raids.
Mr Walsh said AMB-FUBINACA was the most commonly detected chemical in those samples.
Last week, a 21-year old Feilding man died and four others were admitted to Palmerston North Hospital, after taking synthetics.
Ten deaths in Auckland in the last two months have also been linked to synthetics.
MidCentral DHB spokesperson Richard Barrass said users behaved unpredictably and posed a risk to themselves and others.
Mr Walsh said they were nicknamed zombie drugs because their contents could be more than 75 times more potent than the active ingredient in natural cannabis, THC.