Taiwan saw off China's military six decades ago when its forces bombarded offshore Taiwanese islands and that resolve to defend the homeland continues to this day, President Tsai Ing-wen told a visiting group of former U.S. officials on Tuesday.

Tensions between Taiwan and China have spiked over the past month following the visit to Taipei by U.S. House Speaker Nancy Pelosi. China staged war games near Taiwan to express its anger at what it saw as stepped up U.S. support for the island Beijing views as sovereign Chinese territory.

Meeting a delegation of former U.S. officials now at Stanford University's Hoover Institution, Tsai referred to China's more than a month of attacks on the Taiwan-controlled islands of Kinmen and Matsu, just off the Chinese coast, which started in August 1958.

"Sixty-four years ago during the Aug. 23 battle, our soldiers and civilians operated in solidarity and safeguarded Taiwan, so that we have the democratic Taiwan today," she said, using the common Taiwanese term for that campaign, which ended in stalemate with China failing to take the islands.

"That battle to protect our homeland showed the world that no threat of any kind could shake the Taiwanese people's resolve to defend their nation, not in the past, not now, and not in the future," Tsai said.

"We too will show the world that the people of Taiwan have both the resolve and confidence to safeguard peace, security, freedom and prosperity for ourselves."

In 1958, Taiwan fought back with support from the United States, which sent military equipment including advanced Sidewinder anti-aircraft missiles, giving Taiwan a technological edge.

Often called the Second Taiwan Strait Crisis, it was the last time Taiwanese forces joined battle with China on a large scale.

James O. Ellis, now a visiting fellow at Hoover and a retired U.S. Navy admiral, said his delegation's presence in Taiwan reaffirmed the American people's commitment to deepening cooperation.

"Consistent with the Taiwan Relations Act, part of this cooperation involves strengthening Taiwan's capabilities for self defence as well as the ability of the United States to deter and resist any resort to force across the Taiwan Strait," Ellis told Tsai, referring to a U.S. law that requires it to provide Taiwan with the means to defend itself.

Matt Pottinger, who served as former U.S. President Donald Trump's deputy national security adviser, is also part of the delegation.

The United States, which ditched formal diplomatic relations with Taipei in favour of Beijing in 1979, remains Taiwan's most important source of arms.

"As Taiwan stands on the front line of authoritarian expansionism we continue to bolster our defence autonomy, and we will also continue to work with the United States on this front," Tsai said.

China's drills near Taiwan have posed a threat to the status quo in the strait and across the region, and democratic partners should work together to "defend against interference by authoritarian states", she added.

Following that meeting, Tsai met two Japanese lawmakers, and other foreign parliamentarians are also expected to visit this year, including from Canada and Britain, defying Chinese pressure not to go.

Taiwan's government says that as the People's Republic of China has never governed the island it has no right to claim it or decide its future, which can only be set by Taiwan's 23 million people.