TAIPEI (Reuters) -Taiwan's next president Lai Ching-te will express "concrete" goodwill towards China in his inauguration speech on Monday, and call for both sides of the Taiwan Strait to pursue peace, according to a senior official briefed on the matter.

Lai, who takes over from President Tsai Ing-wen having served as her vice president for the past four years, will say that Taiwan will continue to be a promoter of regional peace and stability, the official said.

Beijing views proudly democratic Taiwan as its own territory, over the strong objections of the government in Taipei, and has never renounced the use of force to bring the island under its control.

Lai, 64, and widely known by his English name William, is detested by Beijing as a "separatist" and China has rebuffed his repeated calls for talks.

In his speech, at the Japanese colonial-era presidential office in central Taipei, Lai will pledge to maintain the status quo with China "neither being overbearing nor self-effacing", the official, speaking on condition of anonymity, said.

He will call for both sides of the Taiwan Strait to pursue peace and common prosperity, the official added.

Lai is also set to mention that China has ramped up military and diplomatic pressures on Taiwan.

Last week, China's Taiwan Affairs Office, responding to a question on the inauguration, said Lai, who it called the "Taiwan region's new leader", had to make a clear choice between peaceful development or confrontation.

Lai will say that peace in the strait is an indispensable, key element for stable global development, the Taiwan official said.

Taiwan has faced on-going pressure from China, including regular air force and navy activities close to the island, since January's election victory by Lai.

In attendance on Monday at the ceremony will be former U.S. officials dispatched by President Joe Biden, lawmakers from countries including Britain, Japan, Germany and Canada, and leaders from some of the 12 nations which still maintain formal diplomatic relations with Taipei.

Lai's domestic challenges loom large too, given his Democratic Progressive Party (DPP) lost its parliamentary majority in the January election.

Thousands of supporters of the small Taiwan People's Party, headed by former Taipei mayor Ko Wen-je who came third in the presidential election, protested in front of DPP headquarters on Sunday, saying the DPP has not lived up to its promises in the last eight years in power.

On Friday, lawmakers punched, shoved and screamed at each other in a bitter dispute over parliamentary reforms the opposition is pushing. There could be more fighting on Tuesday when lawmakers resume their discussions.

(Reporting by Yimou Lee and Ben Blanchard; Editing by Lincoln Feast.)

By Yimou Lee and Ben Blanchard