Australia is offering the "world's first" preventative DNA screening for potential cancers and heart disease to thousands of young people free of charge.

The project launched by the Monash School of Public Health and Preventive Medicine, which they claimed to be the world's first DNA screening study for risk, will screen at least 10,000 people between the age of 18 to 40.

"Young Australians can now access a free DNA saliva test to learn whether they face an increased risk of some cancers and heart disease, which can be prevented or treated early if detected," the university said in a statement on Sunday.

It is the world’s first preventive DNA screening study designed specifically to assess population DNA screening through a national health care system.

"The test is free and involves placing a saliva sample into a small tube received by mail, and sending it back in a postage-paid envelope," the statement said, adding that people can register on the university website.

"We hope to identify those at risk while they are young and healthy, not after the fact, and empower them to make more informed decisions about their health," professor Paul Lacaze said.

"For some people, this could save their lives through early detection and prevention of cancer and heart disease. This will also save considerable health system costs in Australia through prevention," he added.

He added that providing genetic testing based on family history alone is not enough as up to 90% of those at high risk in the general population are not identified by current family history-based testing.

"Most people don’t find out about their genetic risk until it’s too late, like after an incurable cancer or heart attack is diagnosed. We want to change that," said Lacaze.

According to the university, those found to be at high risk during the testing will be offered genetic counseling and prevention measures, such as regular scans and check-ups.