A drug that may melt away cancer cells has been approved in Australia for use in patients with a type of leukaemia who have not responded to existing therapies.

The drug, Venetoclax, has been approved by Australia's Therapeutic Goods Administration (TGA) for some stage-four patients of chronic lymphocytic leukaemia.

It works by blocking the action of a protein, known as BCL-2, that enables cancer cells to survive.

It will be available to patients who have not responded to standard treatments or for those who have not been able to undergo other therapies, such as chemotherapy.

Researchers around the world have been looking into a way to stop the protein for more than 30 years.

Professor David Huang, one of the developers of the drug, said the BCL-2 molecule was found to be overactive in many types of cancers, particularly leukaemia, 'ABC' reported.

About 70 patients had received the drug since 2011.

"What we found in our studies was that 80 per cent of patients with chronic lymphocytic leukaemia will actually respond to this drug," said Maryann Anderson from Victorian Comprehensive Cancer Centre.

"Approximately 20 per cent of those patients will achieve a complete remission. Most excitingly, we are seeing that we are getting very good responses amongst patients with the most high risk disease," she added.