(Adds calls for probe into 10 companies, including three foreign)
RIO DE JANEIRO, Oct 23 (Reuters) - A final report approved by a Brazilian congressional panel investigating corruption at state-run oil company Petrobras has blamed suppliers and rogue employees for the graft, rather than politicians or the company.
The committee's final report did not criticize any politicians, including those closely associated with Petrobras, such as President Dilma Rousseff, who was chairwoman of the company's board when much of the corruption happened.
It also spared Eduardo Cunha, the speaker of the lower house who is under investigation by police and prosecutors for alleged corruption.
Rousseff, who is facing a possible impeachment battle, has not been charged or accused by police or prosecutors of any criminal wrongdoing.
The panel did recommend that 10 companies be investigated for possibly paying bribes, including Japan's Kawasaki Heavy Industries, the Brazilian unit of Singaporean oil rig builder Keppel Corporation Ltd, and its Singapore-based rival Sembcorp Marine Ltd.
The report, which followed an eight-month investigation and was approved by a vote of 17 to 9 with one abstention, denied "institutional corruption" existed at Petroleo Brasileiro SA , as the company is formally known.
The report has been criticized for failing to censure any politicians or two previous Petrobras chief executives.
Approval of the report comes the week after Brazil's government said Swiss authorities froze $2.4 million in accounts held by Cunha.
Federal prosecutors are investigating Cunha over allegations made during plea bargains that he received a $5 million bribe as part of the Petrobras corruption scheme.
Cunha, who is a member of Brazil's Democratic Movement Party, part of the ruling Workers' Party-led coalition, previously told the committee he had no Swiss bank accounts.
The committee's official rapporteur, Luiz Sergio Nóbrega de Oliveira, a member of the Workers' Party, said his panel received no proof Cunha had bank accounts abroad.
The final report criticizes police and prosecutors handling of the Lava Jato or "Car Wash" probe into contract fixing, bribery and political kickbacks at Petrobras.
The report also criticizes the use of "an excess" of plea-bargains in exchange for reduced sentences to win confessions from key players in the case. The report says there was no proof that money was diverted from Petrobras projects to politicians.
Brazil's plea-bargain law requires that cooperating witnesses provide evidence as well as testimony in order to receive reduced sentences. (Reporting by Jeb Blount; Editing by Paul Simao and Richard Chang)