Regional Australia is being hit by a rise in the abuse of a prescription painkiller that's already sparked a "public health crisis' in the United States, a NSW opioid deaths inquest has heard.
Fentanyl - a highly potent synthetic opioid - was detected in the blood systems of three out of six fatal overdoses that occurred in the state during May and June 2016.
Only one of the victims had been prescribed the potentially addictive pain relief drug that's 100 times stronger than morphine and has police on alert.
The cluster of deaths occurred over two months, but counsel assisting Peggy Dwyer says prescription opioid overdoses are at record levels in Australia, with hundreds of opiate-related deaths across NSW each year.
"Opioid deaths increased (nationally) by 60 per cent in 2011-2015 compared with 2001-2005," she told Glebe Coroner's Court on Monday.
"Pharmaceutical opioid deaths in Australia now exceed heroin deaths by a significant margin - two to 2.5 times."
Illegal manufacturing of fentanyl in the US has caused a "public health crisis" with a significant spike in addiction rates and related deaths, the court heard.
"One high-profile case was the death of Prince, the music artist, who died after taking a counterfeit painkiller laced with fentanyl," Ms Dwyer said.
But fentanyl is also a "major concern" in regional Australia where use outstrips capital cities, according to Dr Phillip Read, director of Kirketon Road Clinic in Kings Cross.
He's expected to tell the inquest that fentanyl use is on the rise in rural areas where heroin is harder to source.
Dr Alex Wodak, who helped establish the country's first needle syringe program and injecting centre, is also due to give evidence about the recent rise in drug-induced deaths.
"He is concerned that Australia could see this trend continue at an unprecedented rate, particularly if the heroin supply starts to be cut with fentanyl as is common in the United States," Ms Dwyer said.
NSW Health estimates there may be up to 750,000 Australians dependent on opioids and the inquest aims to learn lessons from the deaths to prevent future tragedies.
It will explore the need for real-time prescription monitoring to avoid "doctor shopping" and supervised injection rooms.
The inquest would also consider the need for greater availability of take home naloxone, a "life-saving" drug that can reverse opioid overdoses, Ms Dwyer said.
The drug comes as a nasal spray overseas, but it's only available in injection form locally, one of many barriers to its widespread use.
Harm-reduction strategies will be examined including testing of drugs for impurities, with the inquest hoping to draw on results from the nation's first trial of recreational pill testing at a recent festival in Canberra.
