She agreed to end the fast late on Thursday by accepting a government proposal to conduct a new environmental study on the impact of the project on the mountain's ecology.

"The government has decided to accept a joint study based on the value of appreciating life after considering a proposal by religious leaders and a resolution of parliamentary Construction and Transportation Committee," a government spokesman was quoted as saying by the JoongAng Ilbo newspaper.

Earlier on Thursday, Prime Minister Lee Hae-chan was turned away by members of a Buddhist group caring for Jiyul when he went to see her.

Jiyul's health was believed to have deteriorated fast in recent weeks. She had been taking only water and salt.

Environmental groups say the area north of Pusan is one of a dwindling number of habitats for the salamander.

Jiyul has held three previous fasts to protest the project. Her most recent, which lasted 58 days, ended in August last year when South Korean President Roh Moo-hyun promised to conduct a review of the environmental impact of the plan.

A review committee had since concluded the project could go ahead and a court injunction sought by environmentalists had been rejected, officials at the prime minister's office said.