'What then is the sanctity of a contract, which is the fundamental cornerstone of any law-abiding, market-driven economy? And will this not set a precedent, allowing any ministry to alter any contracts in the future at will?' he queried.

'This will also naturally have adverse policy implications for private investments in all natural resources, which are subject to similar considerations.'

He said he was deeply concerned by the oil ministry's stand that tantamounts to deciding who should sell gas, to whom, at what price and in what quantity without any heed to commercial considerations or contractual provisions.

Reliance Natural Resources and Reliance Industries are fighting a bitter battle over the price and supply of natural gas from what is called the Krishna-Godavari basin, off the Andhra Pradesh coast.

Last month, the Bombay High Court had asked Reliance Industries to supply 28 million units of gas from the fields to Reliance Natural Resources for 17 years at $2.34 per unit after assigning 12 million units to a state-run power utility NTPC.

But Reliance Industries challenged the verdict in the Supreme Court, which heard the case July 20 and fixed Sep 1 as the next date of hearing. It also asked all parties to file their replies on the government position on the matter by then.