Australia was warned in advance of the United States' challenge to Beijing with the calculated sailing of a guided-missile destroyer close to a South China Sea island claimed as territory by China.
China warns US over sea patrols
Beijing expresses its anger as a US guided-missile destroyer, USS Lassen, passes near the man-made islands in the disputed South China Sea.
After the US navy warship the Curtis Wilbur sailed within 12 nautical miles of Triton Island – part of the Paracel Island chain – on Saturday Defence Minister Marise Payne stated Australia's support for the American manoeuvre, which sparked an angry response from Beijing.
The deliberate sailing so close to the disputed island territory – the second time the US has done this in recent months – is meant to head off any attempt by Beijing to curb freedom of navigation and overflight through the strategic waters.
"The United States has publicly declared its policy of conducting freedom of navigation operations globally, consistent with international law," Senator Payne said.
"It is important to recognise that all states have a right under international law to freedom of navigation and freedom of overflight, including in the South China Sea. Australia strongly supports these rights.
"Australia continues to co-operate closely with the United States and other regional partners on maritime security."
Triton Island is also claimed by Taiwan and Vietnam. And while the US stated that its gesture was aimed at all three claimants, it is being widely interpreted as a signal to China, which has lately stepped up its efforts to exert control over the South China Sea, including by building artificial islands complete with military-grade airstrips and ports.
Senator Payne said that Australian ships and planes would "continue to exercise rights under international law to freedom of navigation and freedom of overflight, including in the South China Sea".
Fairfax Media understands that while Australia played no support role to the US in the freedom-of-navigation patrol, Canberra was forewarned by the US that it was planning the exercise, underscoring the close co-operation between the allies on the issue.
South China Sea: Australian air patrol recorded
The BBC records a Royal Australian Air Force surveillance plane conducting an air patrol over the fiercely contested South China Sea.
Senator Payne said that with 60 per cent of Australian exports passing through the South China Sea, Australia had a "legitimate interest in the maintenance of peace and stability, respect for international law, unimpeded trade and freedom of navigation and overflight" in the waters.
An Australian P-3 Orion flew through over sensitive air space in the South China Sea late last year in a move the federal government described as routine but which was widely interpreted as a signal to Beijing that Australia means to continue operating in the regional flashpoint.
It is understood such flights by the RAAF have been stepped up in the past 18 months in a deliberate gesture to Beijing.
Reuters quoted China's foreign ministry as blasting the latest US move as "intentionally provocative" and "irresponsible and extremely dangerous".
"The American warship has violated relevant Chinese laws by entering Chinese territorial waters without prior permission, and the Chinese side has taken relevant measures including monitoring and admonishments," China's foreign ministry said.
Pentagon spokesman Captain Jeff Davis said no ships from China's military were in the vicinity of the USS Curtis Wilbur when it passed near Triton Island.
"This operation challenged attempts by the three claimants – China, Taiwan and Vietnam – to restrict navigation rights and freedoms," he said, according to Reuters.