Lai Ching-te and his running mate Hsiao Bi-khim hold a press conferencein Taipei, Taiwan, on Saturday. Reuters

Taiwan's ruling party candidate Lai Ching-te, branded a threat to peace by China, on Saturday won the island's presidential election, a vote watched closely from Beijing to Washington.

Lai delivered an unprecedented third consecutive term for the Democratic Progressive Party (DPP) after a raucous campaign in which he pitched himself as the defender of Taiwan's democratic way of life.

Lai Ching-te saidon  Saturday that the self-ruled island "will stand on the side of democracy", speaking after he won a crucial election held under the shadow of China's threat of war.

"I want to thank the Taiwanese people for writing a new chapter in our democracy," he said in a victory speech where he thanked his two opponents for conceding.

"We are telling the international community that between democracy and authoritarianism, we will stand on the side of democracy."

Lai said “we will stand on side of democracy. we will continue to walk side by side with democracies around the world. Taiwan will continue to walk on right path forward, we will not look backwards.”

“Taiwan's people have successfully resisted efforts from external forces to influence this election. We did not win parliamentary majority, Taiwan has achieved a victory for the comunity of democracies,” he said.

Communist China claims democratic Taiwan, separated from the mainland by a 180-kilometre strait, as its own and says it will not rule out using force to bring about "unification," even if conflict does not appear imminent.

Beijing has in the past slammed Lai, the current vice president, as a dangerous "separatist" and on the eve of the vote, its defence ministry vowed to "crush" any move towards Taiwanese independence.

Lai had 40.2 per cent of the vote with ballots counted from 98 per cent of polling stations, according to official data from Taiwan's Central Election Commission.

His main rival Hou Yu-ih of the opposition Kuomintang (KMT) trailed in second place with 33.4 percent and conceded defeat.

"When the people have made their decision, we face them and we listen to the voices of the people," Hou told supporters.

"I congratulate Lai Ching-te and (DPP running mate) Hsiao Bi-khim on getting elected and I hope they will not let down Taiwanese people's expectations."

Nearly 20 million people were eligible to vote, and turnout has not yet been announced.

The election was watched closely by both Beijing and Washington, Taiwan's main military partner, as the two superpowers tussle for influence in the strategically vital region.

"This is Taiwan's hard-won democracy. We should all cherish our democracy and vote enthusiastically," Lai told reporters as he voted earlier in the day in a school gymnasium in the southern city of Tainan.

Lai's victory extends DPP's rule after eight years under outgoing President Tsai Ing-wen, who reached Taiwan's two-term limit.

KMT's Hou argued for warmer ties with China and accused the DPP of antagonising Beijing with its stance that Taiwan is "already independent".

The race also saw the rise of the upstart populist Taiwan People's Party (TPP), whose leader Ko Wen-je took 26.4 of the vote with an anti-establishment offer of a "third way" out of the two-party deadlock.

Ko said the result had put TPP on the map as a "key opposition force", breaking up the two main parties' longstanding duopoly.

"Ko Wen-je will not give up on building Taiwan into a sustainable country and I would like to appeal to you not to give up as well," he told supporters.

During the campaign the KMT and TPP tried to strike a deal to join forces against the DPP, but the partnership collapsed in public acrimony over who would lead the presidential ticket.

China censorship

Located on a key maritime gateway linking the South China Sea to the Pacific Ocean, Taiwan is home to a powerhouse semiconductor industry producing precious microchips - the lifeblood of the global economy powering everything from smartphones and cars to missiles.

China has stepped up military pressure on Taiwan in recent years, periodically stoking worries about a potential invasion.

Chinese President Xi Jinping said in a recent New Year's address the "unification" of Taiwan with China was "inevitable."

The hashtag "Taiwan election" was a top trending item on China's social media platform Weibo before being blocked at around 9:45 am (0145 GMT).

After weeks of strong rhetoric over the Taiwan vote from Beijing - but little coverage in Chinese state media to the domestic audience - the 7:00 pm state television news broadcaster Xinwen Lianbo made no mention of the vote.

Chinese warplanes and naval ships probe Taiwan's defences almost daily and Beijing has also staged massive war games in recent years - simulating a blockade of the island and sending missiles into its surrounding waters.

The Chinese military said the night before the polls that it would "take all necessary measures to firmly crush 'Taiwan independence' attempts of all forms."

US Secretary of State Antony Blinken met a senior Chinese official in Washington hours before the vote and stressed the importance of "maintaining peace and stability" across the Taiwan Strait.

As well as a president, voters are also electing lawmakers to Taiwan's 113-seat legislature.

Agence France-Presse