Taipei. The United States should diplomatically recognise Taiwan as "a free and sovereign country," former US Secretary of State Mike Pompeo said in a speech while visiting the island.

Pompeo, one of former president Donald Trump's most hawkish advisors on China, arrived on Wednesday for a visit at a time of rising tensions between Washington and Beijing over the self-ruled island as well as the crisis sparked by Russia's invasion of Ukraine.

While Washington should continue to engage with Beijing as a sovereign government, offering Taipei diplomatic recognition "can no longer be ignored, avoided or treated as secondary," Pompeo said in a speech hosted by a local think-tank.

"It is my view that the United States government should immediately take necessary and long-overdue steps to do the right and obvious thing, that is to offer the Republic of China (Taiwan) America’s diplomatic recognition as a free and sovereign country."

The Republic of China is Taiwan's official name.

Washington has remained Taipei's most important ally and leading arms supplier despite switching diplomatic recognition to Beijing in 1979.

But Pompeo said the move "isn't about Taiwan's future independence, it's about recognition of an unmistakable, already existing reality".

Beijing considers a formal declaration of independence as something that would cross its self-declared "red line" and has warned that such a step could trigger war.

Taiwan's current leader Tsai Ing-wen, who has won elections twice, hails from a party that historically favours independence.

She says there is no need to declare independence because Taiwan is already a sovereign nation called the Republic of China (Taiwan).

Pompeo's speech advocated the same position.

"As many of your past and present leaders have made clear, there's no need for Taiwan to declare independence because it’s already an independent nation. Its name is the Republic of China (Taiwan)," he said.

"The people and government of the United States should simply accept this fundamentally decent, morally right thing. This is easy. The Taiwanese people deserve the world’s respect for continuing down this free, democratic and sovereign path."

President Tsai met Pompeo on Thursday, conferring on him an honorary medal and praising him for facilitating "multiple breakthroughs" in Taiwan-US relations.

On his way out of office, Pompeo announced that Washington was ending restrictions on official contacts with Taipei in a move that angered Beijing.

President Joe Biden has continued most of the Trump era's policies towards Taiwan.