TAIPEI (REUTERS, BLOOMBERG) - Taiwan President Tsai Ing-wen on Thursday (June 13) won the ruling party's hotly contested nomination for the 2020 presidential election, domestic media said, in a boost to her administration.

Ms Tsai beat her former premier, Mr William Lai Ching-te, in a national tally for the independence-leaning Democratic Progressive Party's (DPP) primary race, several television broadcasters and newspapers said.

The self-ruled island is set to hold its presidential election in January, amid heightened tension with China, which considers it a wayward province and has never ruled out the use of force to return it to the fold, if necessary.

The election made front-page headlines in April after Foxconn chairman Terry Gou joined the primary for the China-friendly opposition party Kuomintang (KMT).

Ms Tsai still requires approval from the party's executive committee next week to officially become the DPP's nominee.

The victory grants the President something of a reprieve after her waning public support culminated in her party's devastating losses to the KMT in regional elections in November.

Concerns she would be unable to win a second term in 2020's presidential election spurred her premier to resign and challenge her for the DPP's nomination.

But despite the rebound in her support, she still faces a serious test to avoid becoming Taiwan's first one-term president.

Five hopefuls are vying for the KMT nomination to run against her, including the populist mayor of Kaohsiung City Han Kuo-yu and Foxconn's Gou. Taipei City Mayor Ko Wen-je is also considering a bid as an independent.

The latest polls indicate a tight race.

In an election between Mr Han, Ms Tsai and Mr Ko, the Kaohsiung mayor leads the polls with 30.4 per cent support, 0.4 percentage points ahead of Ms Tsai and 2.8 ahead of Mr Ko, according to a survey conducted by Taipei-based Apple Daily last weekend. The poll had a margin of error of 3.35 percentage points.