Romania on Tuesday delayed a decision on whether to go ahead with a Canadian gold mine project that has provoked mass protests.

A parliamentary vote on a bill that would allow Canada's Gabriel Resources to open Europe's biggest open-cast gold mine was delayed until November after Prime Minister Victor Ponta agreed to set up a committee to examine the project.

Gabriel Resources hopes to extract 300 tonnes of gold from a mine in a picturesque village in Transylvania, and has promised 900 jobs during the 16-year extraction period.

The decision will be a blow to the project's opponents, who had hoped it would be scrapped imminently after Ponta said last week parliament would reject a draft law clearing the way for the mine.

On Sunday, between 20,000 and 25,000 people took to the streets of Bucharest and other cities urging the government to withdraw the draft law, which Romania's president has said he opposes.

Critics say the mine will destroy four mountain tops and threaten Roman era mining galeries.

The project will also use thousands of tonnes of cyanide to extract the precious metal and require hundreds of families to be relocated.

The president of the Association for a Clean Romania accused the prime minister of trying to buy time for the project.

"Ponta wants to please Gabriel Resources more than anyone else, so he will slow things down in the hope that popular protests decrease in time," Alina Mungiu-Pippidi told AFP.