With the 30-member committee almost equally divided, the role of SP, BSP, AIADMK and Trinamool Congress having a total of five MPs in the panel is being watched ahead of the meeting on April 25.
While Congress has 11 members, including the committee chief P C Chacko, its ally NCP has one. BJP has six members and NDA ally JD(U) two.
DMK and BSP have two members each, while SP, BJD, TMC, AIADMK, CPI and CPI-M have one member each in the JPC.
Yashwant Sinha of the BJP, who has been spearheading the attack on the government and Chacko, and T R Baalu of the estranged Congress ally DMK are in touch with other parties like BJD and the Left to oppose the draft report.
The DMK is making common cause with the BJP and others in the context of the draft report pinning the blame on former telecom minister and its MP A Raja without giving him an opportunity of being heard.
Ahead of its Thursday meeting which has been convened to adopt the draft report, a top leader of the opposition gave indications that the opposition will press for a vote on the draft report.
Sources in the Opposition, however, are not fully confident of the position that will be taken by SP and BSP, which provide outside support to the government, and whether they would choose to embarrass the government.
Government managers are dismissive of Opposition plans contending that JPC reports are adopted by consensus and those opposed to it can give their dissent note.
Sensing the opposition mood, Congress today sought to pacify an angry BJP. Chacko, who is also Congress spokesperson, today dismissed reports that the panel has named former Prime Minister Atal Bihari Vajpayee in its draft report.
"We have the highest regard for Atal Bihari Vajpayee. This report has not mentioned the name of Vajpayee. We have not made any reference to the former Prime Minister," Chacko insisted.