The frontrunner to be Taiwan's next president accused the main opposition party on Tuesday of betraying the anti-communist ideals of its forefathers and being overtly pro-China, in a stinging attack ahead of next month's election.

Lai Ching-te, Taiwan's vice president and the ruling Democratic Progressive Party's (DPP) presidential candidate makes a speech.

Vice President Lai Ching-te, the ruling Democratic Progressive Party's (DPP) presidential candidate, said in a second live televised pre-election policy address that while the Kuomintang (KMT) party had once led the fight against China's communists, its current party leaders "not only don't oppose the communists, they are pro-communist".

The Jan. 13 presidential and parliamentary elections are taking place against the backdrop of increased military and political pressure from China to assert its sovereignty claims over democratically governed Taiwan.

China has called Lai a dangerous separatist and portrayed the vote as a choice between war and peace.

"Every time there is an election in Taiwan, China most certainly interferes, hoping to support a pro-China administration," Lai said as he stood next to KMT's presidential candidate Hou Yu-ih.

Lai lauded former president Chiang Ching-kuo - son of Taiwan's postwar strongman ruler Chiang Kai-shek - for his opposition to communism, but added that when China threatens Taiwan, KMT leaders like former president Ma Ying-jeou now criticise Taiwan for provoking China.

"I want all the country's people to judge: is the KMT worthy of Mr. Ching-kuo?"

China has described the election as an internal Chinese matter and that interference accusations are an effort by the DPP to win votes.

Speaking to reporters after the event, Hou denounced what he said was slander and efforts to paint the party red, the colour of China's communist party.

The KMT traditionally favours close ties with China but strongly denies being pro-Beijing. Like the DPP, the KMT says that only Taiwan's people can decide their future.

"We don't need to have an election by fabricating slander and painting (us) red, and we don't need manipulation by ideology," Hou added.

Polls show Lai in the lead by varying margins though Hou has been closing the gap. The third presidential candidate is former Taipei mayor Ko Wen-je from the small Taiwan People's Party, but he has trailed in the polls since an attempt to form a joint ticket with the KMT collapsed in acrimony last month.