Four people have died in recent weeks, including a man and a woman in separate incidents on Thursday, according to ACT Police.
While the exact causes of the deaths have not been determined, police suspect high drug purity levels or the addition of synthetic opioids, such as fentanyl or nitazene, may be responsible.
The synthetic opioids carry a high risk of addiction, breathing difficulties or respiratory failure and death.
ACT Policing detective acting superintendent Dave Craft said synthetic opioids have been identified in the the territory as recently as May this year.
“There is no safe drug use, however we understand drug addiction is a health issue,” Craft said.
“In light of recent overdoses that police have attended we are urging those who are using drugs to do this as safely as possible.
“Police have responded to incidents where people have lost consciousness outside in the middle of the night and haven’t been found until the next morning.
“We don’t want to see more preventable deaths in our community.”
Drugs can be tested at CanTEST, which provides free and confidential chemical analysis of pills and drugs intended for personal use, as well as tailored information and harm reduction advice.
There is also a range of support services and advice for those using drugs from Canberra drug treatment organisations.