Alleging conflict of interest, the Congress on Sunday requested Comptroller and Auditor General (CAG) Rajiv Mehrishi to recuse himself from auditing the deal to purchase 36 Rafale fighter aircraft as he, as the then finance secretary, was part of the negotiations.
The opposition party also said that it would be improper on the part of Mehrishi to present the report in Parliament.
The CAG report on the controversial deal is likely to be tabled in Parliament on Monday.
In a press statement, the Congress has alleged that the government compromised 'national interest' and 'national security' in the purchase of the 36 aircraft and said the CAG has a constitutional and statutory duty to undertake a forensic audit of all defence contracts, including the Rafale deal.
"It is an act of gross impropriety for you to deal with the audit of the 36 Rafale aircraft deal on account of patent conflict of interest... You are constitutionally, legally and morally disentitled to either conduct an audit or to present a report before Parliament.
"We urge upon you to recuse yourself and publicly accept the gross impropriety committed by you in initiating the audit...," it said.
Senior Congress leader Kapil Sibal told reporters that Mehrishi is likely to present the report on the Rafale deal in parliament on Monday.
Sibal said that Mehrishi was the finance secretary from October 24, 2014 to August 30, 2015 and in between Prime Minister Narendra Modi went to Paris on April 10, 2015 and announced the signing of the Rafale deal.
"...Finance Ministry plays an important role in these negotiations...Now it is clear that the Rafale deal happened under Rajeev Mehrishi. Now he is CAG. We met him twice on September 19 and October 4, 2018. We told him about the scam. We told him that the deal should be probed because it is corrupt.
"But how can he initiate a probe against himself," Sibal said.
The Congress said it had, in its submissions to the CAG, listed the acts of omission and commission as well as corruption in the Rafale deal.
"He obviously cannot probe decisions he took as finance secretary. He will protect himself first and then his government.
"There cannot be a bigger conflict of interest than this," he said.