New Delhi, India (CNN) -- India's prime minister said he has nothing to hide and would be "happy" to appear before a parliamentary panel looking into a multi-billion dollar telecom scandal.
"I wish to state categorically that I have nothing to hide from the public at large, and as a proof of my bona fides, I intend to write to the chairman of the Public Accounts Committee that I shall be happy to appear before the PAC if it chooses to ask me to do so," Prime Minister Manmohan Singh said in a speech at a national meeting of the ruling Congress party.
"I sincerely believe that, like Caesar's wife, the prime minister should be above suspicion, and it is for this reason that I am prepared to appear before the PAC even though there is no precedent to this effect."
Opposition parties have stepped up their attacks on Singh, hailed as the father of India's economic reforms, since the country's main auditor reported in November that a sale of a second-generation wireless spectrum two years ago had been carried out at below-market prices.
According to the government audit, the treasury lost up to $31 billion from under-valuation of airwaves.
The alleged scam, seen as the biggest to hit India in recent times, has forced the country's Telecom Minister A. Raja, to step down. Raja, member of a key regional ally of Singh's Congress party, denies the charges.
But opposition lawmakers are seeking a larger probe into the 2008 phone-license awards, and accuse Singh of having not acted swiftly.
India's prime minister, on his part, insists the wrongdoers will be punished.
"It is my promise to you that no guilty person will be spared -- whether he is a political leader or a government official, whichever party he may belong to and howsoever powerful he may be," Singh said Monday.
The damning audit report came on the heels of allegations of massive fraud in sports and real estate.
Investigators are already probing complaints of financial malfeasance in the Commonwealth Games that India hosted in October.
And several politicians, military officials and bureaucrats are the subjects of a separate inquiry for allegedly taking apartments meant for war-widows.
CNN's Harmeet Shah Singh contributed to this report.