The engineering company confirmed it had been contacted by investigators involved in the probe, which has engulfed Brazil's political and business establishment amid allegations of a massive kickbacks scheme.
"We are cooperating with investigating authorities in Brazil but are unable to comment further on a continuing investigation," a Rolls-Royce spokesman said in a statement.
"We have repeatedly made it clear that Rolls-Royce will not tolerate business misconduct of any kind."
Earlier this year the Financial Times reported that a Petrobras executive had told Brazilian police he received a bribe of $200,000 from Rolls-Royce, which makes gas turbines for Petrobras oil rigs.
The British company is also facing a corruption investigation in Britain over allegations of bribery in Asia.
Earlier this month Brazilian prosecutors lodged corruption charges against the speaker of Brazil's lower house over allegations he accepted bribes to help secure Petrobras contracts.
The scandal has engulfed a Who's Who of Brazil's elite, with the arrests of a series of Petrobras executives and political figures.
The case has further weakened President Dilma Rousseff, who has not been directly implicated, but was chairwoman of Petrobras for seven years coinciding with the period of corruption.