A NATIONAL system to track addictive drug prescriptions might reduce overprescribing but could lead to unintended consequences, experts say.

The proposed reporting system for potentially addictive drugs such as morphine is worthwhile if it provides opioids - schedule eight drugs - to those with a genuine need for them, says Dr Fiona Shand from the University of New South Wales' Black Dog Institute.

But if patients are detected "doctor shopping" - visiting different GPs and chemists to fulfil multiple drug scripts - doctors need to respond appropriately, she says.

"Clearly, if a person has been doctor shopping it may be that their pain is not well managed or that they have developed a dependence on the drug and they actually need professional assistance with that," Dr Shand told AAP.

There were also concerns that if patients dependent on prescription opioids could no longer access those drugs, they would simply switch to other illicit or prescription substances, Dr Shand said.

"We want to see prescription opioids available to people who need them," she said.

"We just want to make sure that they are used in a way that doesn't harm people and ... this system can really help with that."

In an article in the Medical Journal of Australia on Monday, Dr Shand and co-authors said the system would need to be closely monitored for unintended consequences.

There was little research available on real-time monitoring systems around the world but a review of a system in Ohio found doctors changed opioid prescriptions in 41 per cent of cases.

Of those, 61 per cent received no opioids or less than previously while 39 per cent got higher doses.

Dr Shand said this suggested that in more than a third of cases, the information available to doctors increased their confidence in prescribing opioids after reviewing the patient's history.

The federal government committed $5 million last February to establish a real-time prescription reporting system for schedule eight drugs.

The move came after evidence, including from coronial inquests, that patients were overdosing on prescription drugs after doctor shopping.

Tasmania is the only state with a real-time prescription monitoring program.

A Victorian coroner recommended the state government implement its own system if the federal program was delayed or proved inadequate, following a spate of prescription drug-related deaths in Victoria.

Originally published as Drug tracking system needs checks: experts