The federal and state governments are being urged to raise the legal smoking age to 21 as part of a plan to combat cancer being pushed by mining magnate and philanthropist Andrew “Twiggy” Forrest.

The proposal, developed by Mr Forrest and his wife’s Eliminate Cancer Initiative (ECI), was unveiled on Monday, with the billionaire also vowing to fight the tobacco industry in the courts.

“We need to stop fuelling big tobacco preying on our vulnerable youth,” Mr Forrest said.

Almost 90 per cent of adult smokers first start the habit as children and the law needed to be changed to address the issue, he said.

“By the time they reach 21, they are hooked and become lifelong customers of big tobacco,” he said.

The Eliminate Cancer Initiative is funded by Mr Forrest and wife Nicola. Photo: AAP

Mr Forrest said tobacco companies needed to be held financially accountable for the damage caused by smoking.

“When tobacco causes many times more cost to the nation than it ever brings in revenue and creates extreme suffering before palliative care and death there is something seriously wrong with any government in the world, particularly ours, tolerating it,” he said.

The ECI is funded by Mr Forrest’s charity the Minderoo Foundation. Part of the $75 million funding the ECI received from the Forrests will be used to launch a legal “assault” against tobacco companies.

The organisation aims to help accelerate cancer research, improve prevention detection and treatment options including access to clinical trials.

Mr Forrest has become a fixture in national public policy debates and is also a strong supporter of the cashless welfare card currently being rolled out by the Turnbull government.

The proposal to lift the smoking age to 21, which has been dubbed Tobacco 21, has already been presented to state and federal governments.

They are scheduled to come together for a Council of Australian Governments in Canberra this week.

The Tasmanian Liberal government briefly considered a proposal to ban people born after the year 2000 from buying cigarettes but has since ruled out the move.

Lifting the smoking age to 21 would put Australia at odds with most other countries around the world. The legal purchasing age is 21 in some state in the US and 20 in Japan.

One Nation leader Pauline Hanson backed the proposal on Monday morning.

“I don’t know how the young ones can afford a packet of cigarettes anyway,” she told Channel Seven.

“The cost of smoking is horrendous. But if it’s going to help the kids and they won’t get onto smoking, they’ll get the smokes from somewhere else, but I think to raise the age limit makes common sense to me.”

The plan has received support from the Cancer Council of Australia, with chief executive Sanchia Aranda saying the measure was a “good place to start”.

“We know that if you can get people to delay starting smoking, then they’re less likely to start at all. So age is very important,” Prof Aranda said.

“But end game lies in a proposal that’s already been considered by Queensland and Tasmania – the introduction of life-long bans on the sale of tobacco products to children born after a certain date – which would require the cooperation of all the states.

“In the meantime, Mr Forrest’s proposal would be a good place to start, alongside deterrence methods including higher taxes, health warnings, and other avenues to help smokers to quit.

-with AAP