Taiwan leader Lai Ching-te's advocacy of the "two-state" theory in his speech would exacerbate tensions across the Taiwan Strait, seriously undermining peace in the Taiwan Strait, a Chinese mainland spokesperson said on Thursday.

Lai continued to promote that the two sides of the Taiwan Strait "are not subordinate to each other" at his first speech at Taiwan's annual event celebrating the "double 10 day" on Thursday since he took office in May.

Chen Binhua, a spokesman for the State Council Taiwan Affairs Office, said Lai's speech was filled with confrontational thinking and provocations, exacerbated tensions across the Strait, and severely undermines peace and stability in the Taiwan Strait.

The realization of the great rejuvenation of the Chinese nation is the greatest dream of the Chinese people since modern times, and it has always been related to the future and destiny of compatriots on both sides of the Taiwan Strait, Chen said.

After 1949, due to the prolonged civil war in China and external interference, the two sides of the Taiwan Strait have been in a prolonged state of political confrontation. However, Taiwan has always been a part of Chinese territory, Taiwan compatriots have always been members of the Chinese nation, the government of the People's Republic of China has always been the sole legitimate government representing all of China, including Taiwan, he said.

"China has always been the great motherland of all Chinese people, and adherence to the one-China principle has always been a universal consensus in the international community," he added.

"The current struggle against 'Taiwan independence' separatism is not a matter of systems but a battle between unity and division," Chen said.

Lai is deliberately scheming to piece together justifications for splitting the country, attempting to hitch Taiwan onto the "Taiwan independence" bandwagon, he said, adding that "his separatist provocations are the root cause of turmoil and instability in the Taiwan Strait, which will bring disaster to the people of Taiwan".

Regardless of what Lai says, it cannot change the legal status of Taiwan as part of China and the fact that both sides belong to one China, he added.

"We have the confidence and capability to achieve the complete reunification of our motherland. No individual or force can stop the historical trend of national rejuvenation and reunification," Chen said.