Brazil's largest oil workers union said on Friday it will start an open-ended strike against Petrobras on Sunday in a bid to overturn moves to shrink the state-run oil company.
FUP, which represents platform, refinery and other workers, will join a number of smaller unions already on strike.
In a statement, FUP said the decision to strike had been made after more than 100 days of negotiations with Petroleo Brasileiro SA, as the company is formally known.
Petrobras, in an emailed statement, said oil production or refining is not affected by the strike. The company was meeting with unions and had made a new salary proposal, it added.
Petrobras wants to pay down debt, which at about $120 billion is the most of any oil company, and generate cash for investment and revive investor confidence after a massive corruption scandal.
FUP said it wants asset sales stopped, work on refineries resumed, local content rules maintained, and a guarantee that Petrobras remain the sole operator in Brazil's sub-salt offshore oil area.
Reporting by Stephen Eisenhammer