Australians with rare cancers are using the Sick or Treat website and petitions to plead for public and government help in getting access to treatment.

At first glance it's a website full of smiling happy Australians, many shown in family settings.

But a closer look reveals a heartbreaking roll of people with rare and less common cancers who are desperately seeking donations to fund their treatment.

Some of those smiling "quite heroic people" didn't make it, Rare Cancers Australia director Richard Vines tells AAP.

As well as using the Sick or Treat website, patients are launching petitions on Change.org calling for urgent federal action so they can get access to potentially lifesaving drugs.

"Cancer doesn't discriminate, so the government shouldn't be discriminating on who gets a shot at fighting it," says Sydney newlywed Jessica Pereira.

The 26-year-old, who's fighting a rare and aggressive blood cancer, says she's being denied subsidised access to the Pharmaceutical Benefits Scheme-listed drug that oncologists say will save her life, because her cancer is deemed "rare".

Rare and less common cancers kill 24,000 Australians a year, with new treatments and research funding lagging behind the more common ones like breast or prostrate cancers, says Professor Mei Krishnasamy, president of the Clinical Oncology Society of Australia.

Mr Vines says the system doesn't cater for rare cancers, being set up for the greatest good for the greatest number.

"The problem with the system is that it relies on massive trial data that it's basically impossible to produce for small population patients," he said.

"We just need flexibility and a process that allows for them to be treated, particularly with drugs that are already listed for other cancers."

Case studies and medical reports from doctors should be accepted as evidence a medication works in rare cancer cases, he said.

Ms Pereira says she's being kept alive by a drug called Crizotinib, which costs $7500 a month and is currently paid for through the Sick or Treat fundraising site.

The drug is deemed experimental for her condition, but is available through the PBS at $37 a month for patients with more common cancers.

"I started my Change.org petition to reform this unfair policy on drug access so that rare cancer sufferers like me aren't left to die because we can't afford treatment," Ms Pereira says.