"Certainly some of the findings of the CAG have now become very doubtful. People are entitled to know what is the truth that has now come out," Kumar told reporters outside Parliament House.
His reaction came after CAG's former director general RP Singh had questioned the body's estimates of presumptive loss of Rs. 1.76 lakh crore.
"After completing the audit of ministry of telecom, which was under my direct charge, I prepared a draft audit report covering each and every aspect ... My report did not contain any loss figure," Singh had said.
The law minister said, "I think the conversation between the chairman of PAC and CAG without knowledge of other members of the PAC should be made public" and added there is "need to preserve the integrity" of Constitutional institutions like CAG.
The CAG report, which was tabled in Parliament in November 2010, had pegged the revenue loss to the exchequer on account of allocation of 2G spectrum in 2008 at 1.76 lakh crore raising a political storm.
The controversy over 2G spectrum allocation also led to cancellation to 122 licences by the Supreme Court.