The fall-out threatens to sour the mood for Ms Bishop's imminent visit to China - her first as Foreign Minister - and comes as the Abbott government pushes aggressively to seal a much-vaunted free trade deal with its largest trading partner within a year. Foreign Affairs Minister Julie Bishop says Australia is opposed to any ''coercive or unilateral actions to change the status quo in the East China Sea''. On Thursday morning, Ms Bishop stood by her public criticism of China, denying she overstepped the mark. ''This is a matter of long-standing Australian policy, we've raised it before and the response from China was to be expected,'' she told Sky News. ''Australia has a key stake in the region and we would oppose action by any side that we believe could add to the tensions or add to the risk of a miscalculation in disputed territorial zones in the region.''

Ms Bishop said she did not believe the comments would affect Australia's hopes of securing a free trade agreement with China next year. When asked by reporters in Sydney on Thursday, Mr Hockey said he was not concerned that China's anger over the East China Sea issue could impede Australia-China free trade negotiations. ''From my perspective, Julie Bishop is doing exactly the right thing,'' Mr Hockey said. The Treasurer added that government was about making hard decisions and being ''honest and frank with each other''. ''The best friend you can have is an honest friend,'' he said.

Ms Bishop had summoned Chinese ambassador Ma Zhaoxu on Monday to express the government's concern over the new zone, which covers airspace over a string of uninhabited islands - known as Diaoyu in China and Senkaku in Japan - at the centre of a longstanding territorial dispute between the two regional powers. Echoing the sentiments of the Japanese and the United States, Ms Bishop said the timing and manner of China's announcement was "unhelpful in light of current regional tensions, and will not contribute to regional stability". "Australia has made clear its opposition to any coercive or unilateral actions to change the status quo in the East China Sea," she said on Tuesday. But in a sternly worded statement on Wednesday, the Chinese foreign ministry warned Ms Bishop to ''correct'' her characterisation of its new air defence zone or risk damaging bilateral ties. "It is completely a mistake for Australia to make irresponsible remarks on China's establishment of an air defence identification zone in the East China Sea, and the Chinese side will not accept it," foreign ministry spokesman Qin Gang said. "China urges Australia to correct its mistake immediately to prevent damaging Sino-Australia relations."

Mr Abbott's public declaration last month that Japan was Australia's "best friend" in Asia had already raised eyebrows in Beijing. A spokesman for the Department of Foreign Affairs and Trade said the government would not retreat from its stance despite the pressure from Beijing and said it was expected to be ''a topic of discussion in Ms Bishop's upcoming visit". "The Australian government remains concerned that China's sudden announcement of an air-defence identification zone over the East China Sea at this time could have potentially destabilising consequences for the region," the spokesman said on Wednesday. "Australia has critical interests at stake in ensuring the continued peace and stability of our region. It was natural that the Australian government should signal its concerns about the timing and manner of China's announcement and to seek clarification." China established its new "air defence identification zone" on Saturday, requiring aircraft entering the zone to notify authorities in advance and maintain radio contact - or risk military intervention.

The move has been met with strong protests by Japan and the US. Both have ignored China's claims to the airspace with Washington flying two unarmed warplanes through the zone in a planned training mission on Tuesday, and the Japanese government instructing its two largest airlines to ignore Beijing's requests for flight plans and other information. Wang Xiangsui, a retired colonel of the People's Liberation Army, said Australia had offended China by taking sides with Japan. "Australia says it is trying to become China's strategic partner, but it doesn't even consider respecting China's security interests." Mr Abbott dismissed the suggestion that Australia’s recent comments would damage trade with China. ‘‘I expect China to be a strong and valuable economic partner of ours, because it is in China’s interest,’’ he said.

The Prime Minister also said that China would understand that Australia would ‘‘take a different position’’ on some issues. On Thursday in Canberra, Prime Minister Tony Abbott backed Ms Bishop's actions. ‘‘Where we think Australia’s values and interests have been compromised, I think it is important to speak our mind,’’ he said. Mr Abbott said that Australia believed in freedom of navigation. ‘‘And I think there is a significant issue here. That’s why it was important to call in the Chinese ambassador.’’

Labor leader Bill Shorten would not provide a specific position on the East China Sea issue, when he was quizzed by reporters on Thursday. "I'm not going to start throwing rocks from the sidelines," he said, adding that it was a "complex" issue and was not a new dispute. But Mr Shorten did tell reporters in Canberra that a number of "spot fires" had emerged on foreign policy under the Coalition government's watch, which included the disputed islands as well as Indonesian relations. "We just want the federal government to get it right." China’s announcement that it would establish a new air defence zone came just days after Ms Bishop signed a joint communique with the US in the annual Australia-US Ministerial Consultations in Washington opposing “unilateral or coercive change in the status quo” in the East China Sea.

It also follows a trilateral agreement signed with the US and Japan in Bali last month. “It’s certainly a slap in the face for the diplomatic position that Australia, the US and Japan have been taking on this issue,” said Rory Medcalf, the director of the international security program at the Lowy Institute. Kerry Brown, executive director of the University of Sydney’s China Studies Centre, said Ms Bishop was forced into siding with the US because of the long-standing alliance. But he said the free trade talks were entrenched enough to remain unaffected by the diplomatic stoush. ‘‘This is a bit like a slanging match in a playground, where you have to stick with your friends even though you might not be too involved because of the need to demonstrate loyalty to them, rather than any direct interest,’’ Professor Brown said.

Loading ‘‘If Australia wavered on this one, they would irritate the US, but not really get very far with the Chinese, so I don’t think they have much choice.’’ With ambassador Frances Adamson out of the country, China on Wednesday hauled in Justin Hayhurst, the deputy head of mission at Australia’s Beijing embassy, to remonstrate.