Beijing warned Taiwan's newly inaugurated leader against seeking independence Friday, saying peace would be "impossible" if the new government attempted to move away from the mainland.

"If 'independence' is pursued, it will be impossible to have peace and stability in the Taiwan Straits," the Taiwan Affairs Office (TAO) said in a statement hours after Tsai was sworn in.

"Independence is the greatest disaster for the peaceful development of peace in the Taiwan straits and the peaceful development of cross-straits relations," it said.

Tsai is the head of the Democratic Progressive Party, which has in the past advocated for Taiwan to separate from the mainland, a goal that Beijing has firmly and consistently rejected.

China and Taiwan split in 1949 after the Kuomintang nationalist forces lost a civil war to the Communists. But Beijing has always seen the island as a renegade province awaiting reunification, by force if necessary.

The TAO statement referred to Tsai as "the new leader of the Taiwan administration", without naming her.

Her campaign emphasised the island's unique identity, and in her speech she promised to raise its profile in the international community, an idea that has long met with stiff resistance from Beijing, which has spent immense political and financial capital opposing such efforts, whittling away the number of countries that recognise Taipei diplomatically.

Addressing the issue, foreign ministry spokeswoman Hua Chunying said that while Beijing has no objection to "unofficial trade relations", it is "opposed to other countries signing official agreements with Taiwan".

China's state-run media were almost mute about the inauguration itself, with no coverage on national television or in major newspapers such as the People's Daily, the Communist Party's mouthpiece.

But in the days leading up to the inauguration, state broadcaster CCTV said the PLA had staged at least three landing exercises in the country's southeast, an apparent warning to Tsai not to test Beijing's resolve.

"Today, our determination to defend national sovereignty and territorial integrity is unchanged", the TAO said.

"Our capabilities are stronger. We will firmly contain any separatist acts or plans for 'Taiwan independence' in any form."