New Delhi, Dec 20 (IANS) The opposition Monday reiterated its demand for a joint parliamentary committee (JPC) probe into the 2G spectrum allocation scandal despite Prime Minister Manmohan Singh expressing his willingness to appear before parliament's Public Accounts Committee (PAC).

"When he is ready to come and answer any question before PAC... Why not JPC? JPC is constitutional body. He knows PAC's role will be limited to a CAG report. What about other issues? Everybody wants a clear and transparent investigation and punishment to the guilty. That's possible through JPC only," BJP spokesperson Prakash Javadekar said.

Javadekar said the JPC "is a legitimate demand" of the opposition. "We will continue demanding it. It is a parliamentary instrument. Why are you not ready for the JPC. It can investigate the issues outside the CAG report."

Communist Party of India (CPI) leader D. Raja also said the opposition will pursue its demand for the JPC probe into the telephony spectrum allocation of 2008, an issue that led to parliament's winter session being washed out to anti-government protest by MPs.

"PM has again ruled out any constitution of JPC. I don't understand why. Why is he making it such a contentious issue. The JPC will go into the depth of this scam. I don't think PAC can be better than JPC," Raja said.

Manmohan Singh in his speech at the Congress' 83rd plenary said he was ready to appear before the PAC investigating the telecom scam. He ruled out any formation of a JPC.

"I sincerely believe that like Caesar's wife, the prime minister should be above suspicion. And for this reason, I am prepared to appear before the Public Accounts Committee even though there is no precedent to that effect," he said.