There's concern a drug more potent than fentanyl has been found in New Zealand

Australian health authorities have issued warnings about synthetic opioid protonitazene - linked to one death and multiple overdoses.

Its been found mixed with other drugs including GHB and methamphetamine.

The New Zealand Drug Foundation's confirmed it was identified here in February.

Drug Foundation Executive Director Sarah Helm says finding it mixed with other drugs would be a worst-case scenario.

She says if it was sold as something else, we'd be in a particularly bad situation.