Both sides are expected to affirm the importance of stability in the Taiwan Strait, South China Morning Post (SCMP) reported citing Nikkei Asia.

This would mark a rare public expression of concern about Taiwan by US and Japanese leaders.

Beijing claims full sovereignty over Taiwan, a democracy of almost 24 million people located off the southeastern coast of mainland China, despite the fact that the two sides have been governed separately for more than seven decades.

"The security of Taiwan is no longer an issue between the two sides of the Taiwan Strait... China's hegemony in the region and military aggression over Taiwan has highlighted the global concern about Taiwanese security," said Wang Ting-yu, a legislator from Taiwan's ruling Democratic Progressive Party.

Observers say that the US and Japan, along with Australia and countries from Europe, now see mainland China becoming a regional threat as it expands its military power, reported SCMP.

"This explains why Japan, which used to be rather conservative when it comes to the Taiwan issue, is considering sending its defence forces to cooperate with the United States to defend Taiwan," said Chen Ting-fei, another DPP legislator However, former Taiwanese defence minister Andrew Yang, however, said Japan was unlikely to take the initiative over Taiwan given the risk of angering Beijing. "Rather it would focus on issues including mutual defence, the [disputed] Diaoyu Islands and Beijing's frequent activities around the Diaoyus (Senkakus)," he said.

The meeting between Suga and Biden is scheduled for April 16. This will be the first in-person meeting of Biden with a foreign leader since taking office in January this year. This will also mark Suga's first visit to the United States as prime minister.

China in February enacted a new law that authorizes its coast guard to seize foreign ships entering waters claimed by Beijing, putting more pressure on Taiwan. Japan is also affected since it controls the Senkaku Islands, which China claims and calls Diaoyu.

China claims sovereignty over almost the entire South China Sea and has overlapping territorial claims with Brunei, Malaysia, the Philippines, Vietnam and Taiwan.

The communist nation has been increasing its maritime activities in both the South China Sea and the East China Sea over the past few months, partly in response to Beijing's concerns over the increasing US military presence in the region because of escalating Sino-US tensions.