New Zealand's being warned not to become complacent about opiate abuse, following a spate of deaths in Australia.

A new report has revealed the opiate fentanyl was implicated in ten deaths in Melbourne in 2015.

The highly powerful drug was mixed with heroin.

New Zealand Drug Foundation executive director Ross Bell said fentanyl is available as a prescription painkiller in New Zealand.

"The other thing that we'd have to watch out for is any of the legitimate prescription medicine being diverted on to the black market."

In the US, the opioid epidemic has been declared a public health emergency, with more than 90 Americans dying every day.

Bell said New Zealand can't afford to be complacent.

"The way that drugs are traded globally now, people can buy these things online and have it delivered through the mail to New Zealand."

Fentanyl is a prescription drug, and is often mixed with heroin.

Only a few millilitres of the drug is enough to kill someone.