A potential joint bid for Taiwan's presidency by the island's two main opposition parties was in disarray on Saturday as they bickered on how to agree on who will run for president with time running out to make a decision.

The issue of China, which views Taiwan as its territory, looms over the Jan. 13 parliamentary and presidential elections. China has stepped up military and political pressure, including high-profile war games, to press the island to accept its sovereignty claim, which Taiwan rejects.

After weeks of sometimes acrimonious talks on joining up for the presidential election, the Kuomintang (KMT) and the much smaller Taiwan People's Party (TPP) agreed on Wednesday to look at an aggregate of opinion polls to decide which party's candidate would run as president and which as vice president.