Beijing has threatened a "counterstrike" against international moves to preserve the democracies of Hong Kong and Taiwan.
Foreign ministers from the United States, Canada, Britain and Australia condemned the arrest of more than 50 opposition parliamentarians and democracy activists in Hong Kong in a Five Eyes joint statement last Sunday.
New Zealand refrained from contributing to the statement, choosing instead to voice its concerns separately.
NZ Foreign Affairs Minister Nanaia Mahuta issued a statement on social media that said the arrests represent "another effort to erode the rights and freedoms of the people of Hong Kong and further undermine the one country two systems framework".
The Five Eyes statement called upon China to respect democratic freedoms in Hong Kong.
"It is clear that the National Security Law is being used to eliminate dissent and opposing political views," the statement read.
"We call on the Hong Kong and Chinese central authorities to respect the legally guaranteed rights and freedoms of the people of Hong Kong without fear of arrest and detention."
China's foreign ministry spokesman Zhao Lijian responded right away, saying "relevant countries are confusing right and wrong, misleading the public and blatantly intervening in China's Hong Kong affairs." The arrests in China were in accordance with national security laws, Zhao said, and those laws were safeguarding China's sovereignty and security.
Beijing says it "strongly condemns and firmly opposes" meddling in its "domestic affairs" by the United States, Britain, Canada and Australia.
The problem is the definition of "domestic affairs". Taiwan is an independent democratic state. Hong Kong is the subject of a handover treaty as it transitions from British colonial rule.
"The Chinese people's resolve to defend our sovereignty and territorial integrity is unshakeable and we will not permit any person or force to stop the process of China's reunification," Zhao said in the press briefing on Monday.
"Any actions which harm China's core interests will be met with a resolute counterstrike and will not succeed."
Relations between China and Australia have been particularly strained. Australia's criticism of human rights violations in China, its call for an international investigation into the origins of Covid-19, and its new military pact with Japan have all angered Beijing.
China has already introduced tariffs and bans on a range of Aussie imports, including wine, barley, lamb, beef, coal, lobster and timber, and there are fears that more industries could be in the firing line.
"Many Chinese people feel as if they have swallowed a fly when hearing about Australia," the CCP-controlled Global Times declared last month. "Australia treats China's goodwill with evil. It is not worthy to argue with it. If it does not want to do business with China, so be it."
A senior academic adviser to the Chinese Communist Party says the worsening relationship with both Australia and Japan is proving a hurdle to improved relations between Beijing and other South East Asian countries and that the diplomatic spat "is without end in sight".
China warns Taiwan
Outgoing US Secretary of State Mike Pompeo pulled the pin on another political hand grenade at the weekend, leaving the Biden administration to deal with the fallout.
He has scrapped all curbs on interactions between US and Taiwanese officials – measures introduced decades ago in order to appease a hard-bargaining Communist China as it tentatively opened up its economy to the world.
China's response has been predictably bellicose. Beijing says it won't accept any diplomatic recognition of Taiwan, which it insists is an "inviolable part of China" and will enforce "severe punishment" against any attempt to do so.
The Global Times warned that international recognition of an independent Taiwan would be "overwhelming".
"Those on the island of Taiwan must not take for granted that they can seek secession ... On the contrary, such madness is very likely to bring them annihilation."
The stage has been set for a major escalation in tensions between Beijing and Washington.
The US ambassador to the United Nations will visit Taiwan for three days starting on Wednesday. The visit is significant as the UN and its representative bodies – including the World Health Organisation – do not recognise Taiwan's independent status.
This has long been China's demand. But the weaknesses of this policy became apparent during the crisis response to the emergence of Covid-19 as Taiwan – and its pandemic expertise – was repeatedly sidelined at international forums.
Taiwan Foreign Minister Joseph Wu said the visit was a "big thing".
"The foreign ministry will not let our guard down and hopes to continue to boost the development of Taiwan-US ties," he said.
The visit is part of outgoing Secretary of State Pompeo's declaration that "all contact guidelines regarding relations with Taiwan ... to be null and void".
Taiwan has welcomed this final act of the troubled Trump presidency, but the Global Times has declared: "The dire consequences will be beyond anyone's predictions."
"If Washington arbitrarily removes these restrictions it had previously complied with, China-US relations will be totally redefined, and the two countries will move into hostility. The international basis and foundation for a peaceful resolution of the Taiwan question will collapse."