(Recasts with proposed new contract)
SAO PAULO, Aug 6 (Reuters) - Brazilian petrochemical giant Braskem SA on Thursday reported a sharp jump in quarterly profit, and its chief executive said it had proposed a flexible new supply contract with state-run oil firm Petrobras .
In a press conference to discuss Braskem's second-quarter results, CEO Carlos Fadigas said the company had offered to buy naphtha from Petrobras, its second-biggest shareholder, at a price within 10 percent of the ARA international benchmark, but the companies had not reached a deal.
Brazilian prosecutors last month charged executives at engineering group Odebrecht SA, Braskem's biggest shareholder, with paying bribes to Petrobras executives to secure a naphtha contract that allegedly cost the oil giant billions of dollars.
Braskem, the biggest petrochemical firm in Latin America, and Odebrecht have denied any wrongdoing, but Petrobras confirmed irregularities in the process of approving the 2009 contract to supply Braskem with naphtha, the main raw material for many of its plastic resins and other products.
Fadigas made the comments after Braskem announced a sharp jump in quarterly profit on Thursday due to surging exports aided by a more favorable exchange rate and strong global prices for plastic resins.
Braskem reported a second-quarter profit of 1.055 billion reais ($300 million), up from 204 million reais a year ago, according to a securities filing.
Earnings before interest, taxes, depreciation and amortization rose 76 percent to 2.614 billion reais.
Braskem shares were up 6 percent in midday trading, the biggest gain on the benchmark Bovespa stock index. ($1 = 3.52 Brazilian reais) (Reporting by Alberto Alerigi Jr. and Priscila Jordao; Writing by Brad Haynes; Editing by Paul Simao)