Some 20,000 Romanians took to the streets on Sunday protesting against a Canadian company's plan to open Europe's largest gold mine in the heart of Transylvania, in the biggest rallies since the mobilisation started two weeks ago.

Canadian firm Gabriel Resources hopes to extract 300 tonnes of gold in Rosia Montana with mining techniques requiring the use of thousands of tonnes of cyanide.

The decision by the centre-left government to approve a draft law speeding up the opening of the mine has been the trigger for protests.

In Bucharest, more than 10,000 people marched for several hours in the city centre chanting "United we can save Rosia Montana" and calling for the government's resignation.

Among the protesters were many young couples with children on their shoulders or in prams and people riding bikes.

"It is very shocking to see that a law is specially designed for the benefit of a private company. It could create a dangerous precedent," Sorin Jurca, a Rosia Montana resident, told AFP in Bucharest.

Jurca has been opposing the mine for years and fears his property could be expropriated by the company if the draft law is approved in Parliament.

Nearly 7,000 protesters turned out in Cluj, the largest Transylvanian city, almost 1,000 in Iasi, 850 in Brasov and several hundreds in Sibiu, Oradea, Timisoara and Craiova, according to police figures.

Prime Minister Victor Ponta Told Antena 3 TV channel that he would "seek dialogue" with the protesters.

On Sunday, Ponta went to the planned gold mine site to meet 33 employees of the Rosia Montana Gold Corporation (RMGC) who were refusing to leave a former mining gallery.

The employees fear they will lose their jobs if the project is blocked by lawmakers.

Ponta convinced them to stop their protest in the gallery by promising a special parliamentary committee would be set up to examine the project.

"We will create a committee and will have its members come here to talk" to the employees, Ponta said, quoted by Mediafax news agency.

Outside the mine, hundreds of people cheered him, urging the government and lawmakers to back the Canadian mine plans.

"We want to work, not to beg," they chanted.

It is now up to the Romanian Parliament to vote on the draft law.

The date of the vote has not yet been set.

On September 9, after more than 15,000 people took to the streets, one of the ruling coalition parties said the mining project should be blocked.

Ponta then said that Parliament "will reject the project".

But since then, many of his ministers have defended the draft law saying it will benefit Romania.

"We don't trust the promises of the politicians, that is why we will keep on protesting until the mining project is really blocked," Ionut Butu, a 28-year-old architect, told AFP.

Gabriel Resources, which owns 80 percent of the Rosia Montana Gold Corporation, acquired a mining licence in 1999 but has been waiting ever since for a crucial permit from the environment ministry.

The company promises 900 jobs during the 16-year extraction period and economic benefits.

Scientists and opponents warn the mine will threaten the area's Roman mining galleries.

The project requires hundreds of families to be relocated.