Beijing claims Taiwan as its own territory and baulks at any official contact Taipei has with other countries.

Responding to a question on whether China's military would take countermeasures against Lai's Pacific tour, Wu Qian said: "We firmly oppose official interaction with China's Taiwan region in any form."

"The Chinese (military) shoulders the sacred mission of safeguarding national sovereignty... and will resolutely crush all secessionist attempts for Taiwan independence," Wu, a spokesperson for China's defence ministry, told a press conference.

Taiwan's Lai will stop over in Hawaii and the US territory of Guam during a trip to three Pacific island nations, Taiwan's Presidential Office said, in his first overseas trip since taking office in May.

Lai will depart Saturday for a visit to the Marshall Islands, Tuvalu and Palau -- the only Pacific islands among Taiwan's 12 remaining allies.

Beijing opposes international support that gives a sense of legitimacy to Taiwan and has blocked Taipei from many global forums and whittled down its diplomatic allies.

It has refused to rule out the use of force to seize Taiwan and in recent years has ramped up military activity around the island.