CORRECTED - Petrobras may appeal $700 mln regulator's charge

(Corrects figure in headline to $700 million from $700)

RIO DE JANEIRO, July 24 (Reuters) - Brazil's state oil company Petrobras (PETR4.SA)(PBR.N) will protest a 1.3 billion reais ($706 million) charge for an error in calculating government take from its Marlim field, the company said on Tuesday.

"All payments made by Petrobras were in compliance with the rules. If we cannot resolve this in an administrative way, Petrobras will appeal in court," a company spokesman said.

Petrobras stock opened 1.2 percent lower at 56.8 reais after rising 1.6 percent on Monday.

The head of the National Petroleum Agency (ANP), Haroldo Lima, said on Monday the oil market regulator notified Petrobras of the charge and the company had agreed with his agency's findings and acknowledged the error.

But Petrobras said the agency was trying to collect a new charge retroactively, which had no juridical justification.

The ANP said Petrobras has 30 days to make the payment. It also said it was also investigating another Campos basin field for signs of similar infringements. Lima also said Petrobras had inflated its costs thus reducing government take payments at Marlim.

The so-called "special participation" take is charged from high-volume, highly profitable oil and gas projects. The Marlim heavy oil field has been the main source of Brazil's oil exports. ($1=1.84 reais)