A dozen people have been hospitalised due to suspected fentanyl overdoses, all in the Wairarapa region.
All of the 12 had symptoms of an opioid overdose, and some of them were in serious condition.
Fentanyl is a synthetic opioid much more potent than morphine and is rare in New Zealand's underground drug market.
Detective Inspector Blair Macdonald is the manager of the National Drug Intelligence Bureau and spoke to Morning Report.
