A large Australian study of people with chronic pain found many find pain relief from cannabis.

Cannabis might provide more relief from chronic pain than prescription drugs, new research suggests.

The large Australian study found that use of the illegal drug for pain relief is common among people with chronic pain, such as low back pain, neck pain and migraines.

The study also found that cannabis users report greater pain relief in combination with prescription opioids, such as morphine and oxycodone, than when opioids are used alone, the researchers said.

The study of 1500 Australians, led by researchers at the National Drug and Alcohol Research Centre at UNSW, is expected to intensify the debate about allowing cannabis use for medical purposes.

Lead researcher Louisa Degenhardt said 13 per cent of study participants had used cannabis in the past year, compared with only five per cent of the general population.

A quarter of those surveyed said they would use cannabis for pain if they had access to it.

Professor Degenhardt said that there was currently limited research evidence on the effectiveness of cannabis use for chronic pain.

"Despite scientific uncertainty about the benefits of cannabis use for medical purposes there is a significant sub-population of people living with chronic pain who report that they experience real benefits in terms of pain relief," she said.

Addiction medicine specialist from Sydney University and co-author on the study Nicholas Lintzeris said more research is required.

"We have documented that a small but significant population of chronic pain sufferers reported pain relief from their cannabis use," Associate Professor Lintzeris said.

In the study, published in the international journal Drug and Alcohol Dependence, those who used cannabis reported more severe pain than non-cannabis users and less symptom relief with the prescription drugs, he said.

"It may be that cannabis use provides some additional therapeutic benefits for those not benefiting from usual treatment approaches.

"However, there is often a complex relationship between pain and other health issues, such as mental health, sleep and substance use, and much more research is required to disentangle the effects of cannabis use in chronic pain sufferers."