In a hawkish speech to the Lowy Institute think tank in Sydney on Thursday, Mr Abbott suggested China in the Xi Jinping era had "dropped the mask" worn since Deng Xiaoping-led economic reforms in the late 1970s and 80s.

It was now seeking a leadership role in the international system and throwing its economic weight around in pursuit of its goals - rather than upholding its former "hide your strength, bide your time" mantra.

Mr Abbott - prime minister when Mr Xi addressed Australian parliament in late 2014 - said he was concerned about the future of Hong Kong as anti-government protests continue to mar the city.

Hong Kong demonstrators are angry at what they see as Chinese meddling in the freedoms promised to the former British colony when it returned to Chinese rule in 1997, and have been protesting for more than six months.

Beijing has blamed foreign forces for fomenting unrest.

Mr Abbott said Australia should respond assertively if the "One Country, Two Systems" model governing China-Hong Kong relations is seriously undermined amid protests, including any attempt to persecute anti-Chinese Communist Party parliamentarians or pro-democracy leaders.

"It wouldn't be possible for a credible Australian government to ignore any abrogation of the 'One Country, Two Systems' arrangement with Hong Kong. That would have to be met with targeted sanctions at least as significant as those imposed on Russia for its proxy invasion of the western Ukraine (in 2014)," Mr Abbott said.

"If that sort of thing (persecutions) was to start to happen, I think they would be the tremors of the sort of crackdown we'd have to take very seriously."

Mr Abbott said part of the solution to quelling Beijing's regional ambitions was promoting the military and economic rise of India in the Indo-Pacific, pairing with the United States as "two democratic superpowers".

He also said the Australian navy should take part in freedom of navigation patrols in the South China Sea, where Beijing has since 2013 developed and militarised contested atolls and reefs.

The US has conducted frequent patrols since 2017 in defence of the United Nations Convention on the Law of the Sea, under which China's land reclamation activities were in 2016 deemed unlawful.

"America shouldn't have to do all the heavy lifting on behalf of the wider world. I certainly would be supportive of Australia doing freedom of navigation ... I think it's probably time for Australia to do one," Mr Abbott said.

Meanwhile, at a separate address, Mr Abbott's former foreign minister Julie Bishop urged Canberra to be "a voice of reason and moderation" while also warning of Beijing's tendency to place countries "in the freezer".

She advised against relenting to Chinese pressure on issues of national interest.

"It's how you resolve it. You don't cave in and suddenly throw all your interests and priorities and values and principles to the wind," Ms Bishop said at the Sydney launch of a Quarterly Essay on China.

She insisted it was possible to raise tricky diplomatic issues with senior members of the Chinese government while maintaining a trading relationship.

"China can draw a distinction, so should we," Ms Bishop said.

"One must be clear and consistent in identifying what are the sensitive issues and where we see transgressions, and ensure that China is fully aware of our views so that they are not taken by surprise."

Australian Associated Press