Taiwan's ruling party will not let war break out with China, but it is China that is to blame for stirring up tensions, Taipei's former top diplomat in the United States and now frontrunner to become its next vice president, said on Friday.

Hsiao Bi-khim, vice president candidate for the ruling Democratic Progressive Party (DPP), talks to the media outside the Central Election Commission in Taipei.

The Jan. 13 presidential and parliamentary elections will define Chinese-claimed Taiwan's ties with Beijing, and are happening as China steps up military activities around the island to assert its sovereignty claims.

China has rebuked current Vice President Lai Ching-te, the ruling Democratic Progressive Party's (DPP) presidential candidate and leading in the polls, as a dangerous separatist, portrayed the vote as a choice between war and peace, something Taiwan's main opposition party the Kuomintang (KMT) has echoed.

In a live televised pre-election policy address by the three vice presidential candidates, Lai's running mate Hsiao Bi-khim, Taiwan's high-profile former de facto ambassador to the United States, said her opponents had consistently blamed the DPP for tensions in the Taiwan Strait.

"But the whole world knows that the real reason is that China has been expanding outward in an authoritarian posture in recent years, trying to change the existing international order and status quo. Even during the KMT's rule, the expansion of China's armaments never stopped," Hsiao said.

"We are strengthening our defences to avoid war. I want to declare to my compatriots that Lai Ching-te and Hsiao Bi-khim advocate defending the status quo of peace in the Taiwan Strait; we will not let war break out in the Taiwan Strait."

Standing next to her on the stage, the KMT's vice presidential candidate, the fiery media personality Jaw Shaw-kong, said his party was "absolutely not pro-China".

"The DPP do not understand mainland China, and totally do not understand the Communist Party," said Jaw, whose party traditionally favours close ties with China.

"The DPP are using the China threat as a chip to get them elected, to dupe the electorate."

Taiwan and China have to talk, Jaw said, criticising the DPP for not doing so, and pledging the KMT would re-start dialogue while also ensuring Taiwan's defences.

President Tsai Ing-wen and her government, including Lai and Hsiao on the campaign trail, have repeatedly offered talks with China but been rebuffed.

China has denounced Lai and Hsiao as dangerous separatists and described the election as an "internal Chinese affair".

Both the DPP and KMT say only Taiwan's people can decide their future.

Cynthia Wu, the vice presidential candidate for the small Taiwan People's Party which is trailing in the polls, made scant mention of China in her address, concentrating instead on domestic issues like the need to set up a sovereign wealth fund.