'Over the expected lifetime of the Krishna-Godavari basin fields, this increase will amount to a staggering Rs.50,000 crore, even assuming that the exchange rate remains constant at current prices.'

The group also sought to question the stand of petroleum ministry that there was scarcity of gas in the country, even though Reliance Industries was producing much below the present capacity of 52 million units per day.

'This perception of scarcity - a totally artificially created phenomenon - is being exploited by Reliance Industries to extract a higher price of gas and make super normal profits,' the letter said.

Quoting unattributed media reports, the letter said the Reliance Industries was seeking to rely on the oil ministry's affidavits in the Bombay High Court in the dispute with Reliance Natural Resources to strengthen its case against NTPC.

'Yet, the petroleum ministry it would appear is not considering intervening in the court case between Reliance Industries and NTPC,' the letter said, while adding the same stand was not being maintained in the dispute between two private corporate houses.

The petroleum ministry has filed a special leave petition in the Supreme Court with the plea that Krishna-Godavari gas was national property, even as the Bombay High Court was hearing the dispute between NTPC and Reliance Industries.

The apex court is set to hear the case Sep 1.