Brazil's Supreme Court has given the green light for the attorney general to begin investigating dozens of top politicians for alleged connections to a big kickback scheme at state-run oil company Petrobras.

Among those the court says will be investigated are former president and current senator Fernando Collor, who was forced from the presidency by a corruption scandal in 1992.

Also on the list are the current leaders of Brazil's senate and lower house. In total, 54 people are to be investigated.

Federal prosecutors say they've uncovered the largest corruption scheme ever in Brazil. They say that for over a decade, Brazil's biggest construction and engineering firms paid at least $800 million to former Petrobras executives and others in exchange for inflated contracts.