Romanian Prime Minister Victor Ponta on Monday gave in to mounting street protests against a planned Canadian gold mine, admitting that a bill aimed at speeding up the project would fail in parliament.

A negative vote will not necessarily torpedo the mine project, which could still obtain a permit from the environment ministry through a lengthier procedure.

Ponta's acknowledgement came a day after more than 15,000 people took to the streets for the eighth straight day to protest against the project that will use thousands of tonnes of cyanide to extract the precious metal.

"A majority of lawmakers are opposed to the draft law, so it will be rejected," Ponta told reporters.

Canadian company Gabriel Resources, through its 80 percent owned subsidiary Rosia Montana Gold Corporation, plans to open Europe's largest open-cast gold mine in the Transylvanian village of Rosia Montana.

Last month Ponta's centre-left government submitted a bill that would it make easier for the company to expropriate people's property and obtain certain permits from local authorities.

Gabriel Resources aims to extract 300 tonnes of gold and 1,600 tonnes of silver.

Reacting to media reports, the company said it would "assess all possible actions open to it, including the formal notification of its intentions to commence litigation for multiple breaches of international investment treaties" if the draft law was rejected.

Ponta's surprise announcement followed a statement by Senate speaker Crin Antonescu that the bill should be spiked, citing the massive protests.

Antonescu and Ponta are co-presidents of Romania's ruling centre-left coalition USL, but have sometimes taken opposite stands on major issues.

Experts and activists worry that the use of cyanide will poison groundwater and that open-cast mining will destroy four mountain tops around Rosia Montana, which is home to unique Roman mining galleries.

The company promises 900 jobs in the 16-year extraction phase and says the mine would "provide substantial economic, environmental, cultural and social benefits to the region and... the local community."

"Since there is a clear majority against this draft law there is no point in protracting things," Ponta said, adding that the two houses of parliament would rapidly debate and reject the bill.

"That will be the end of it," he said.

Ponta had earlier this month sparked sarcasm after saying that although the project was beneficial to Romania he would vote against it in parliament.

Opponents on Monday hailed Ponta's statement but said they remained cautious.

"This is indeed a victory, but during the decade-long war we have been waging against this project we have lived similar moments when we thought we had won," Mircea Toma, head of the rights group Active Watch, told AFP.

"Nothing is ever solved for good in Romanian politics, which is both good and bad, as you can postpone bad decisions indeterminately," said Alina Mungiu-Pippidi, president of the Association for a Clean Romania.

She added that "holders of shares in this non-existent gold mine will keep up the pressure", so it was too soon to say that the project would be buried.

But she hailed "a victory for unaffiliated urban protesters" who took to the streets for days putting an end to years of apathy among Romanian youth.