The federal government is putting $3 million towards researching how medicinal cannabis can be used to combat cancer pain and other side effects.

Olivia Newton-John wants Australia to catch up with the rest of the world on medicinal cannabis.

It comes as the federal government announces $3 million for clinical trials looking at how cannabis can be used to help treat cancer pain and other side effects.

Cancer patient-turned advocate Newton-John says the funding is a great start but is "frustrated" that only about 11,000 Australians have access to medicinal cannabis.

The singer and actress wants Australia to catch up with the United States when it comes to using the drug for cancer treatment.

"They've discovered it hasn't caused all the problems that people are afraid of," she told journalists at the annual Wellness Walk and Research Run in Melbourne on Sunday.

"People need to let go of that old hippie thing (about the drug).

"It's helped me incredibly, with pain, with sleep, with anxiety, particularly when I had to wean myself off morphine. And I used cannabis."

Health Minister Greg Hunt says there's a lack of well-designed clinical studies looking at medicinal cannabis.

He adds the government is committed to ensuring a safe and quality supply of the drug, but only when it is prescribed by a medical professional.

Nearly 80 companies have been licensed to grow and harvest medicinal cannabis in Australia the past two-and-a-half years.