Taiwan President Tsai Ing-wen waves to the supporters at the celebration of the 14th presidential inauguration on May 20, 2016 in Taipei, Taiwan.

China must use peaceful means to resolve its differences with Taiwan and respect its democratic values, Taiwanese President Tsai Ing-wen said on Tuesday, ahead of a major speech about the island by Chinese President Xi Jinping in Beijing.

China has heaped pressure on Tsai since she took office in 2016, cutting off dialogue, whittling down Taiwan's few remaining diplomatic allies and forcing foreign airlines to list Taiwan as part of China on their websites.

China fears Tsai wishes to push for Taiwan's formal independence, though Tsai says she wants to maintain the status quo. Beijing has regularly sent military aircraft and ships to circle the island on drills.

Taiwan is gearing up for presidential elections in a year's time. Tsai's pro-independence Democratic Progressive Party suffered stinging losses to the China-friendly Kuomintang in mayoral and local elections in November.

In a new year's address at the presidential office in Taipei, Tsai said the two sides of the Taiwan Strait needed a pragmatic understanding of the basic differences that exist between them in terms of values and political systems.

"Here, I would like to call on China to face squarely the reality of the existence of the Republic of China on Taiwan," Tsai said, referring to the island's formal name.

China "must respect the insistence of 23 million people on freedom and democracy, and must use peaceful, on parity means to handle our differences," she added.

China's interference in the island's political and social development is "Taiwan's biggest challenge at the moment," Tsai said. China denies any interference in Taiwan's internal affairs.

China views Taiwan as a wayward province, to be brought under its control by force if needed, with no right to international recognition as a separate political entity.

Democratic Taiwan has shown no interest in being ruled by autocratic China.

Liu Jieyi, head of China's Taiwan Affairs Office, said in his new year's message they had not wavered last year in the face of "deliberate provocations" from Taiwan's government.

"Although the way ahead won't all be plain sailing, we have the confidence and the ability to vanquish risks and challenges," he said in a statement on the office's website.

On Wednesday, Xi will give a speech to mark 40 years since a key policy statement that eventually led to a thaw in relations with Taiwan, the "Message to Compatriots in Taiwan."

On Jan. 1, 1979, China declared an end to what had been routine artillery bombardment of Taiwan-controlled offshore islands close to China and offered to open up communications between the two sides, after decades of hostility.

Chiang Kai-shek fled with defeated Nationalist forces to Taiwan in December 1949 after losing a civil war to the Communists.

Despite the deep business, cultural and personal links which exist today, no peace treaty or formal end to hostilities has been signed.