Taiwan's government said Thursday it would seal off a nuclear power plant due to open next year but repeatedly attacked as unsafe by the public, pending a referendum on its future.

Deputy economic affairs minister Woody Duh said maintenance fees could reach Tw$4 billion ($133 million) to shutter the power station for three years -- the estimated time required to organise and hold the referendum.

In April, the government said it would halt construction after an estimated 28,500 protesters blockaded a main street in Taipei demanding the plant be scrapped. Police used water cannon to dislodge hundreds who refused to leave the scene, in clashes that left 40 people injured.

Intense political wrangling has repeatedly delayed the project, which began in 1999 and has already cost around Tw$300 billion (US$10 billion).

The fourth plant is almost complete and was originally due to come on line in 2015, according to its operator the state-owned Taiwan Power Company (Taipower).

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

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

The main opposition Democratic Progressive Party opposes the new facility on safety grounds, though the ruling Kuomintang party says the island will run short of power unless it goes ahead.

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