Party leader Prashant Bhushan said this move will result in the government losing approximately Rs 52,000 crore.
He alleged that Veerappa Moily had moved a cabinet note stating that the Ratna oil field, a medium size oil field 130 km south-west of Mumbai, be given to the Essar group at price fixed in 1993.
"In 1993, the Union government decided to give the Ratna oil field to the Essar Group. The Letter of Award was given to the company in 1996, but the contract was not signed," Bhushan said at a press conference here.
"But in his last days in office Moily has asked his officers to prepare a cabinet note on the issue and that the oil field contract should be given to the Essar group," he added.
He said that despite Ministry officers warning of a huge loss of government revenue, Moily was going ahead with the move.
An Essar spokesperson, however, said it had won the Ratna R-series field in an open bidding and it was in national interest that the reserves be developed to cut imports.
"Essar was awarded the Ratna R-series block in an open and transparent manner through a bidding process. We are not aware of any internal notes or documents of MoPNG in the matter. However, it is in the national interest to make any block operational especially when there has been significant delay and the country is importing over 70 per cent of its crude requirement at a high cost in foreign exchange," the spokesperson said.