TAIPEI, Feb. 15-- Taiwan opposition Democratic Progressive Party (DPP) chair Tsai Ing-wen registered on Sunday morning as a candidate in the party primary for Taiwan's leadership election next year.

Tsai paid 5 million new Taiwan dollars (about 161,000 U.S.dollars) as registration and polling fees. She is the only DPP member in the running. Tainan Mayor William Lai and former DPP chairman Su Tseng-chang, both previously considered challengers, have decided not to run.

It will be the second attempt by Tsai, 59, to win the leadership election. She lost to incumbent leader Ma Ying-jeou of the Kuomintang (KMT) in the 2012 race. The KMT has not yet started its nomination process.

Commenting on Tsai's chances, KMT representative Charles Chen said his party was not surprised. He hopes Tsai will no longer engage in empty talk, come up with responsible and feasible policy and debate with the KMT.

The KMT plans its own primary after lunar New Year.

Formerly a university law professor, Tsai joined the DPP in 2004 and was elected legislator. She was first elected DPP chair in 2008, the first female leader among Taiwan's major political parties. She was re-elected twice in 2010 and 2014. Tsai was Taiwan's mainland affairs chief from 2000-2004 when Chen Shui-bian was leader and assumed the post of deputy chief administrator in 2006-2007.

The DPP began its nomination process for the election last week. Candidates can register until Feb. 16.