Washington is reportedly pushing both Japan and Australia to clarify their positions for a hypothetical conflict over the democratically-government island, which Beijing considers part of its territory.
Acting Defence Minister Pat Conroy on Sunday reiterated the nation's long established stance on whether it would choose to join the US in war.
"The decision to commit Australian troops to a conflict will be made by the government of the day, not in advance," he told ABC's Insiders program.
"Sovereignty will always be prioritised."
Elbridge Colby, a key Pentagon strategist, has been pressing defence officials from both countries to declare their positions in meetings over the issue, according to a report in the Financial Times.
He is also leading a US review of its nuclear submarine deal with Australia under the three-nation AUKUS partnership following concerns the plan to supply the vessels would harm the American navy.
The US will be among 19 countries participating in Exercise Talisman Sabre, which begins on Sunday and will involve 30,000 defence force personnel.
The event was the nation's most important joint military exercise with the US, Mr Conroy said, and it was expected to be closely monitored by China after the Asian superpower observed the last four such operations.
"We will obviously observe their activities and monitor their presence around Australia, but we'll also adjust how we conduct those exercises," he said.
"People observe these exercises to collect intelligence around procedures, around the electronic spectrum and the use of communications."
Prime Minister Anthony Albanese landed in Shanghai late Saturday, kicking off a six-day tour which will focus on economic and security issues.
Defence analysts have flagged Mr Albanese will likely raise live-fire drills conducted by the Chinese military off Australia's coast earlier in the year after Beijing failed to notify authorities ahead of time.
The Chinese flotilla also circumnavigated the country in a projection of power.
But Mr Conroy would not be drawn on whether Mr Albanese will directly raise those concerns with Chinese President Xi Jinping when the two leaders sit down during his second visit as prime minister.
