Using cannabis on a regular basis doubles the risk of psychotic symptoms including schizophrenia, according to official advice provided to the federal health minister. The briefing paper, obtained by the Australian, revealed extensive links between cannabis use and poor mental health. Attorney General is waiting on the nation's capital to release a final version of its legislation designed to decriminalise personal cannabis use. Christian Porter will then decide whether the government should override the territory legislation.

The federal government is providing $3 million to investigate how medicinal cannabis can help cancer patients.

It comes as Health Minister Greg Hunt reveals more than 11,000 Australians have been approved to access medicinal cannabis products, most of them this year.

The multi-million dollar research grant will be used to look at how cannabis can help treat cancer pain and other side effects.

Mr Hunt says the government is committed to building on the evidence supporting medicinal cannabis.

Mr Hunt made the announcement this morning with Olivia Newton-John who is in Melbourne for her Wellness Walk and Research Run.

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.”

Ms Newton-John told the Sunday Herald Sun that she hopes Australia can “become the epicentre of cannabis research”.

Nearly 80 Australian companies have been licensed to grow and harvest the product in the last two-and-a-half years.