Japan moved ahead with an expansion of support to US troops as the allies held top-level talks on Friday over tensions with China and North Korea.

US Secretary of State Antony Blinken announced the two nations were signing a five-year extension of the support package provided by Japan for the hosting of around 50,000 US troops on its soil.

The new agreement "will invest greater resources to deepen our military readiness and interoperability", Blinken said at the opening of four-way virtual talks between the allies' foreign and defence chiefs.

"Our allies must not only strengthen the tools we have but also develop new ones," Blinken said Thursday in Washington.

Tokyo pays the costs of the US forces in the country as well as utilities. A previous agreement was set to expire in March 2021, but was extended for a year around a change of administration in Washington.

US Defense Secretary Lloyd Austin, appearing from isolation after a mild case of Covid-19, said the allies were "evolving our roles and missions to reflect Japan's growing ability to contribute to regional peace and stability".

Japan renounced its right to wage war after World War II and has since developed a close alliance with Washington, which is treaty-bound to defend the world's third-largest economy.

According to the foreign ministry, the new five-year package will amount to 211 billion yen ($1.8 billion) per fiscal year, an increase of about five percent.

The package comes amid growing tensions with China, which has stepped up incursions near Taiwan, a self-ruling democracy that enjoys close ties with Washington and Tokyo but which Beijing considers a province awaiting reunification.

"Beijing's provocative actions keep raising tensions across the Taiwan Strait and in the East and South China Sea," Blinken said.

He also described North Korea's missile programmes as an "ongoing threat" after Pyongyang fired a suspected ballistic missile into the sea.

A joint statement issued after the talks took aim at "efforts by China to undermine the rules-based order", with specific reference to activity in the East and South China Seas.

The allies also expressed "serious and ongoing concerns" about rights violations in China's Xinjiang region and Hong Kong, and called for "peace and stability" in the Taiwan Strait.

Chinese foreign ministry spokesman Wang Wenbin on Friday expressed Beijing's "strong dissatisfaction and firm opposition to the US, Japan, and Australia crudely interfering in China's internal affairs".

"The US, Japan and Australia talk about freedom, openness and tolerance, but in fact they are ganging up to form small cliques targeting other countries, showing off their military strength and carrying out military intimidation," he told a regular briefing.

On Thursday, Japan and Australia signed what they called a "landmark" treaty to strengthen defence ties.

Japan's Foreign Minister Yoshimasa Hayashi told reporters on Friday that he had again raised the issue of Covid clusters on US bases, which are believed to have spilt over into local communities in several areas.

Japan's government on Friday approved new virus restrictions in three regions that host US bases or are near them, and Hayashi said he had urged "the US side to strengthen anti-infection measures including efforts like introducing limits on off-base outings".