Romania's spy chief says his agency has been spying on a planned Canadian gold mine project for years, monitoring protests and foreigners who allegedly paid lobbyists for and against the project.

Spy chief Gheorghe Maior told a parliamentary committee that his agency had sent 500 memos to decision-making authorities from 1999 to 2013 about the planned gold mine in northwest Romania, which has drawn large street protests in recent weeks.

Maior said the action was legal because the mine was "a problem of national security." He said some protests had been manipulated by people he called "eco-anarchists."

The disclosure was surprising, however, because it was reminiscent of the country's dreaded Securitate secret police, which once used an estimated 760,000 informers from all walks of life.