The frontrunner for Taiwan's 2016 presidential election, opposition leader Tsai Ing-wen, on Friday pledged that if elected she would seek peaceful ties with mainland China while maintaining democracy on the island.

Tsai's remarks come after Taiwan's President Ma Ying-jeou held a historic summit with Chinese leader Xi Jinping in Singapore last month, but concerns remain in Taiwan over warming ties with Beijing.

Taiwan and the mainland split in 1949 after a civil war, but relations have markedly improved since Ma's 2008 election with his China-friendly Kuomintang (KMT) party having come to power on a platform of boosting trade and tourism with Beijing.

"If elected... we would do our best to seek ways (forward) that could be accepted by both Taiwan and the mainland," Tsai said during a televised debate late Friday.

"We will not be provocative, and hope the two sides can sit down and talk in a rational manner."

Tsai, chairwoman of the nominally pro-independence Democratic Progressive Party (DPP), added that any such efforts would not come at the expense of democracy.

Although it is a self-ruling democracy with a fierce sense of its own identity, Taiwan has never formally declared independence from Beijing, which sees it as a renegade province to be reunified with the mainland, by force if necessary.

Meanwhille, Ma and his KMT party have bound the island closer to the mainland, with the start of direct flights that have ramped up tourism, and a many-fold increase in Chinese investment.

His policy of alignment has become increasingly unpopular in Taiwan, however, and the KMT looks set to get a thumping in the presidential election due next year, which the DPP appears set to win.