The opposition on Monday received fresh ammunition against the government, a day before an all-party meeting called to ensure that the Budget session runs smoothly.

A reported deal between ISRO (Indian Space Research Organization) and a private firm for allocation of scarce spectrum, which media reports claim could cost the exchequer more than the 2G scam, has provided further grist to the opposition mill.

BJP and the Left parties demanded immediate scrapping of the allocation, a clarification from Prime Minister Manmohan Singh and a thorough probe into the reported deal between Antrix Corporation with Devas Multimedia Private Ltd , which allegedly confers unbridled use of 70MHz of scarce S-band spectrum over a 20 year-period. Antrix is ISRO's commercial arm.

Reports claimed that preliminary estimates by the Comptroller and Auditor General (CAG) has placed the loss to the exchequer on account of the deal at Rs 2 lakh crore.

In a statement, the CAG said its attention was drawn to media reports regarding audit being undertaken by Audit and Accounts Department of the department of space (DoS).

"The news item gives the impression as if our audit has been finalized. This office clarifies that audit of certain activities of DoS is under way. Very preliminary queries have been raised which are yet to be replied by that department.

Since the audit is at very preliminary stage, it can by no stretch of imagination be concluded that information as given in the media reports are findings of this department," the CAG statement said.

Since the department of space is directly under the PM, he should immediately clarify his stand on the issue, BJP spokeswoman Nirmala Sitharaman said. "We demand a comprehensive inquiry to establish the criminality in the whole matter. We demand recovery of the lost revenue," she added.

The Congress refused to comment on the merit of the case saying it was for Parliament's Public Accounts Committee to examine any matter that caused a loss to the exchequer. "There is a standard procedure. Whenever the CAG finds something that causes loss to the government, it automatically goes to the PAC. I hope this matter also goes to the PAC ," Congress spokesman Shakeel Ahmed said.

The Left parties said the allegation was serious and demanded thorough enquiry into the "new scam". "This is a new issue. The Indian Space Research Organisation is under the department of space which is under the PM. This is also a new scam," CPM leader Sitaram Yechury said.

CPI's D Raja said Left would discuss the scam and might demand its inclusion in the terms of Joint Parlimentary Committee that the opposition is demanding for 2G scam.