Vice Admiral Joseph Aucoin, Commander of the massive, Japan-based 7th Fleet, stressed the call was Australia's, but went further than any senior US defense figure has gone previously in bluntly saying it would be valuable for other countries including Australia to challenge Beijing's "assertiveness" rather than leave it to the US.
Admiral Aucoin's remarks in Sydney come just a week after it emerged that China has placed missiles on islands in the contested waters of the South China Sea, the Sydney Morning Herald newspaper reported.
Admiral Aucoin said he wished the challenge to Beijing's territorial claims in the strategically vital waters were not "portrayed as the US versus China" but rather that "all countries, no matter what the size or strength can pursue their interests based on the law of the sea".
Asked whether that meant all countries with an interest in passage through those waters should be doing similar operations to the US's two recent "freedom of navigation" patrols close to Chinese-claimed territory, he said: "Personally, it's up to those countries but I think it's in our best interests to make sure those sea lines remain open and I'll leave it at that."
Asked then whether that could be interpreted as saying it would be valuable for Australia to do freedom of navigation operations within 12 nautical miles of China's claimed territory, he replied: "Yes."
Sailing within 12 nautical miles constitutes a challenge to territorial claims as this is the distance sovereignty extends from land into the sea.
Admiral Aucoin's comments go considerably further than any US figure has done before. Admiral Aucoin, who is visiting several cities including Canberra, said he was discussing the South China Sea with Australian counterparts but had "not specifically" discussed patrols within 12 nautical miles.
As commander of the 7th Fleet - the US's largest - Admiral Aucoin is in charge of the two US ships that have so far carried out such patrols.
Chinese Foreign Minister Wang Yi and Australian Foreign Minister Julie Bishop in Beijing last week.