Taiwan's bustling democracy of 23 million people is separated by a narrow 180-kilometre (110-mile) strait from communist-ruled China, which claims the island as part of its territory.

Saturday's election is being closely watched around the world as the winner will lead the strategically important island -- a major producer of vital semiconductors -- as it manages ties with an increasingly assertive China.

Vice President Lai Ching-te, the front-runner candidate of the ruling Democratic Progressive Party (DPP), paints the election as a choice between "democracy and autocracy" -- criticising his main opponent Hou Yu-ih of the Kuomintang (KMT) for being too "pro-China".

Waving flags and carrying posters, their supporters converged in two stadiums located right next to each other in New Taipei City.

"We want peace, not war," blared the KMT supporters' signs, while DPP loyalists carried the party's signature green flags saying: "Choose the right people, walk the right path".

In Taipei, supporters of third-party candidate Ko Wen-je gathered outside the Presidential Office on the sprawling Ketagalan Boulevard, shouting that "Taiwan's choice is Ko Wen-je".

The leader of the small Taiwan People's Party (TPP), Ko has criticised his opponents for being caught up in ideological deadlock, attracting voters who say they are sick of talking about China.

Beijing in recent years has maintained a near-daily military presence around Taiwan, sending in warplanes and ships to its surroundings in "grey zone" harassment actions which fall short of outright provocation.

The weeks leading up to Saturday's vote have also seen a flurry of Chinese balloons crossing the Taiwan Strait's sensitive median line -- with a record five balloons appearing Thursday -- which Taipei has slammed as a form of election interference.

Beijing has never renounced the use of force to bring Taiwan under its control.

On the eve of the election, China's defence ministry denounced the DPP for pushing "Taiwan toward the dangerous conditions of war".

"China's (People's Liberation Army)... will take all necessary measures to fimly crush 'Taiwan indepedence' attempts of all forms, and firmly defend national sovereignty," said defence ministry spokesperson Zhang Xiaogang.

All the sabre-rattling from across the Taiwan Strait means that Taiwan must build up its "self-defence to prevent the other side from bullying us", said DPP supporter Yoyo Chen.

"If China wields war, I will stay in Taiwan," said the 30-year-old tailor at the DPP rally.

"I will fight them even if all I have left is a broomstick."

- 'A victory for Taiwan' -

The election on the small, verdant island has drawn massive attention overseas, as Taiwan's next leader is set to determine future cross-strait relations with China in a flashpoint region that has Beijing and Washington tussling for influence.

In a sign of the importance Washington attaches to the election, US Secretary of State Antony Blinken will hold talks with a senior Chinese official in Washington on Friday.

Blinken will meet Liu Jianchao -- who heads the international division of the Chinese Communist Party's Central Committee -- as the United States seeks to discourage Beijing from taking action against Taipei.

The candidates hit the campaign trail hard this week, crisscrossing Taiwan for temple stops, market visits and small rallies, while making the case to a large pack of visiting international media that they are the best choice for the island's voters.

All three candidates -- from the DPP, KMT and TPP -- have said they will maintain the island's status quo, and rejected "one country, two systems", a Beijing doctrine used for governing Hong Kong and Macau.

No matter who wins on Saturday, it remains unclear which candidate Beijing prefers, said Marc Julienne, head of China research at the French Institute of International Relations.

"Today there is no political party that is pro-People's Republic of China," he said, referring to China's official name.

"At the end of the day, it's the Taiwanese who elect their president, vice president and parliament, so it will be a victory for Taiwan."