Workers at Rio de Janeiro's iconic Maracana stadium, one of the key venues for the 2014 World Cup , halted work on Monday and are threatening a full-scale strike beginning next week if their demands for better salaries and benefits are not fulfilled.

The workers said the stoppage is a warning as negotiations with the construction companies are under way. They want higher salaries and better meal vouchers and health plans.

The union representing the workers said they are expected to return to work on Tuesday but a strike could start as early as Monday if their demands are not taken into consideration.

The renovation at Maracana is already behind schedule. It was originally expected to be completed in December.

The famed stadium will host three matches during the Confederations Cup from June 15-30, including the final. It will also host the World Cup final.