Taiwan is preparing to elect a President and legislature on Saturday in what many see as a test of control with China, which claims the self-governing island republic as its own territory to be unified with force if necessary.

The presidential race is tight, and both China and Taiwan’s key ally, the US, are weighing in on political and economic issues they hope will sway voters.

The election pits Vice-President Lai Ching-te, representing the Democratic Progressive Party, against Hou Yu-ih of the main Opposition Nationalist Party, and former mayor of the capital Taipei, Ko Wen-je, of the Taiwan People’s Party.

The US strongly backs Taiwan against China’s military threats and the Biden administration plans to send an unofficial delegation comprised of former senior officials to the island shortly after the polls.

That move could upset efforts to repair ties between Beijing and Washington that plunged in recent years over trade, Covid-19, Washington’s support for Taiwan and Russia’s invasion of Ukraine, which China has refused to condemn at the UN.

Along with the tensions with China, much in the Taiwan election hinges on domestic issues, particularly over an economy that was estimated to have only grown by 1.4 per cent last year.

That partly reflects inevitable cycles in demand for computer chips and other exports from the high-tech, heavily trade-dependent manufacturing base, and a slowing of the Chinese economy.

But longer-term challenges such as housing affordability, a yawning gap between the rich and poor, and unemployment are especially prominent.

Candidates will make their final appeals on Friday with campaigning to end at midnight. The candidate with the most votes wins, with no runoff.

The legislative races are for districts and at-large seats.