In an address to the Australian National University, National Security College Head Professor Rory Medcalf said the country needed to start preparing for future challenges to ensure its security.

Prof Medcalf pointed to the thawing of relations between Canberra and Beijing, with a meeting between the two nation's leaders taking place last month for the first time in six years, saying Australia couldn't continue its reliance on China.

"We're also back on speaking terms with Beijing, but it would be a colossal misjudgement to assume this constitutes some kind of reset or provides a solid foundation for ongoing dependence on China," he said on Wednesday night.

"At best, this is a fragile stabilisation.

"Highly plausible China-centric crises in the region - and an assault on Taiwan is just one scenario - would shatter any sector's brittle business model of reliance on China."

China's $20 billion trade sanctions on Australia remain, with Beijing also continuing to detain Australian citizens.

Prof Medcalf said a country did not need to become Sparta, and abandon its democratic values to be able to look after itself.

He backed a form of national service - but rejected conscription - where Australia could build a highly-trained reserve to be able to respond to crises including natural disasters or for wartime.

"Within the next decade, Australia will not credibly be able to provide for its security without radical changes to our thinking about whose job it is," Prof Medcalf said.

He said commonwealth public service jobs should be open to permanent residents, which would create a pool of Australians for positions that require a security clearance.

Public service jobs should also be a fast track to citizenship, Prof Medcalf added.

Australian Associated Press