'In the interests of transparency and probity, it is requested that the petroleum ministry may kindly ensure the expeditious completion of the CAG audit,' said the letter written by group president A.N. Sethuraman.

'While this full and comprehensive audit is on, the ministry should publicly disclose the CAG's current findings as well as the identity of other auditors involved in the exercise, if any, and their terms of reference,' it said.

'Considering the independence of earlier experts has been questioned, it is also requested that petroleum ministry may kindly arrange to revalidate the capex of KG D6 block by a reputed international expert with experience in deep water blocks.'

Anil Ambani's Reliance Natural Resources is fighting a bitter legal battle with Reliance Industries over supplies of gas from the Krishna-Godavari basin at the contracted price of $2.34 per unit.

In June, the Bombay High Court asked Reliance Industries to supply 28 million units of gas from the KG fields to Reliance Natural Resources for 17 years at $2.34 per unit.

But the Mukesh Ambani group challenged the verdict in the Supreme Court, which heard the case July 20 and fixed Sep 1 as the next date of hearing. The court has asked all parties to file their replies on the matter by then.