Reliance Industries Ltd said on Wednesday it would appeal to the Supreme Court against a ruling that it should enter into a gas supply agreement with former group firm Reliance Natural Resources Ltd.

In June the Bombay High Court had ruled that Reliance Industries, controlled by billionaire Mukesh Ambani, and Reliance Natural, headed by estranged younger brother Anil Ambani, should enter into a supply agreement.

Reliance Industries, India's top listed firm, was asked to supply gas to Reliance Natural at nearly half the price given under an interim ruling, the latter's lawyer had said.

"We have been advised to and are filing appropriate proceedings in the Supreme Court against the judgment delivered by the Bombay High Court on 15th June 2009," Reliance Industries said in a statement.

On Tuesday Reliance Industries said it could not sign the gas supply agreement with Reliance Natural Resources as it wanted the terms such as price, quantity and tenure to be subject to government approval.

Ahead of the announcement, shares in Reliance Industries rose 1.7 per cent to 2,057.35 rupees and Reliance Natural, engaged in sourcing, supply and transportation of gas, coal and liquid fuels, fell 1.4 per cent to 82.75 rupees in a firm Mumbai market.