Five people have died from suspected drug overdoses in Canberra in the past fortnight, prompting a warning about potentially lethal illicit drugs in circulation.

The five deaths occurred in separate incidents, with police suspecting opioids were involved in each case, although the exact causes are yet to be determined.

Police are also aware of at least two non-fatal drug overdoses in the past week.

People who use drugs and those around them are being urged to watch for signs of an overdose, including drowsiness, loss of consciousness, unusual breathing and skin turning blue or grey.

Police say anyone who suspects an overdose should immediately call triple zero and administer naloxone if available. An ambulance should still be called if naloxone has been given.

Naloxone, which can temporarily reverse the effects of an opioid overdose, is available free from CanTEST, CAHMA, the Civic and Woden Needle and Syringe Programs and some pharmacies.

Drugs can also be tested free and confidentially at CanTEST.

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