New Delhi: Industrialist Ratan Tata and lobbyist Niira Radia are likely to appear before Parliament's Public Accounts Committee (PAC) on Monday in connection with the alleged irregularities in the allocation of 2G spectrum.

Radia, whose tapped phone conversations with politicians, corporates, bureaucrats, and journalists, form a key part of investigations into the 2G spectrum scam, will appear before the panel.

The panel, headed by senior BJP leader Murli Manohar Joshi, is expected to quiz Radia on the taped conversations which include allegations of trying to influence portfolio allocation to ministers in UPA-II government.

Radia, chairperson of Vaishnavi Corporate Communications, is heard making efforts to ensure that DMK leader A Raja gets the Telecom portfolio. Raja is now in jail in connection with the 2G spectrum allocation scam. Tata is scheduled to appear before the PAC at 3 PM on Monday.

The PAC is expected to record the evidence of Tata on the recent developments in the telecom sector, including allocation of 2G and 3G spectrum.

On Tuesday, the PAC had asked Reliance Communications Chairman Anil Ambani, Etisalat DB Telecom CEO Atul Jham, S-Tel CEO Shamik Das and Unitech Wireless Managing Director Sigve Brekke to appear before it.

A Joint Parliamentary Committee (JPC), chaired by Congress leader P C Chacko, has also been set up to look into all the details of the 2G spectrum allocation in 2008 and in the telecom sector from 1998 onwards.

The two leaders, Joshi and Chacko had a meeting with Speaker Meira Kumar on Saturday and asked her to give directions to demarcate the areas of examination by the JPC and the PAC.

The PAC has also sought details from the Department of Telecommunications on issues of 2G spectrum allocation and other developments in the sector.

The details have been sought on side-tracking the views and concerns of the Ministry of Finance by Raja, the first-come, first-serve policy and ignoring the advice of the Ministry of Law and Justice to refer the issue of new licences in 2007 to the group of ministers (GoM).