Former Taiwanese opposition leader and anti-nuclear activist Lin Yi-hsiung Tuesday launched an indefinite hunger strike in protest at a nearly completed nuclear facility, while some of his supporters clashed with police.

"It's very meaningful to be doing something good for Taiwan -- I feel very calm," Lin told a crowd of reporters and supporters before he began the hunger strike.

He added he had been forced into the situation because the authorities had ignored public opinion on nuclear power. He said the majority of people in Taiwan were against a fourth nuclear power plant.

Lin, who led the main opposition Democratic Progressive Party (DPP) from 1998-2000, has devoted himself to battling the island's nuclear power policy in the past two decades.

"If anything unfortunate should happen to me, I want my family and friends to know that (those in power) murdered me," the 72-year-old said before entering a church in Taipei to begin his indefinite fasting.

Outside parliament, dozens of protesters briefly clashed with the police as they attempted to surround the building in a show of support for Lin.

They unfurled a large yellow banner reading "Salute chairman Lin Yi-hsiung, stop building fourth nuclear (plant)", and held placards calling for the project to be terminated.

"If Lin Yi-hsiung loses his life, it is the evil government who have caused it," said the group's leader Tsai Ting-kuei.

Taiwan's three existing nuclear power plants supply about 20 percent of electricity.

Construction of the fourth began in 1999 but intense political wrangling has repeatedly delayed the project. State-run Taiwan Power Co (Taipower) says it is 98 percent completed and due to start operating in 2015.

The DPP opposes it on safety grounds, while the ruling Kuomintang party says the island will run short of power unless it goes ahead.

Last year the government agreed to hold a referendum on the new nuclear plant but it has failed to agree the terms of the vote with the opposition.

Concerns about the island's nuclear facilities have been mounting since 2011, when the Fukushima nuclear plant in Japan was hit by a tsunami which knocked out power to cooling systems and sent its reactors into meltdown.

Like Japan, the island is regularly hit by earthquakes. In September 1999 a 7.6-magnitude quake killed around 2,400 people in the deadliest natural disaster in the island's recent history.