Taiwan cannot afford chaos or "experiments" when it comes to being president, the frontrunner to be the island's next leader said on Wednesday as the opposition remained mired in a bitter dispute on mounting a joint presidential challenge.

The Jan. 13 election will shape Chinese-claimed Taiwan's relations with Beijing at China steps up military pressure to assert its sovereignty claims.

Vice President Lai Ching-te of the ruling Democratic Progressive Party (DPP), who China views as a separatist, leads opinion polls, while talks between the two main opposition parties to team up have floundered.