Congress President Sonia Gandhi has asked her party MPs to be present in the Rajya Sabha during voting on the Lokpal Bill to counter the BJP.
Earlier on Wednesday, Gandhi blamed the BJP for the defeat of Constitution Amendment Bill on Lokpal, saying it exposed its "real face".
Gandhi said the BJP had actually committed itself to supporting Constitutional status to Lokpal in the Standing Committee deliberations.
"But yesterday, we saw their real face. The strength we wanted to give to Lokpal Bill, they did not want it and voted against it," Gandhi told reporters in New Delhi.
The government faced an embarassment in Lok Sabha last night as it could not muster the requisite two-third majority for passing the bill that provides Constitutional status to Lokpal and Lokayuktas.
There was some confusion in the morning regarding when the bill will be placed in the Upper House for voting as the amended bill needed president's approval.
President Patil later in the day gave her nod to the amended Lokpal Bill paving the way for its introduction in the Rajya Sabha. It is now up to the government to decide if it wants to introduce the bill in the upper house on Wednesday afternoon or Thursday. There are reports that the bill will be tabled at 2pm on Wednesday though it is not clear when the voting will take place.
Even though the govt gets some time before the Lokpal Bill is voted upon in the Rajya Sabha, the role of SP and BSP remains very important as the UPA does not have the required numbers. The UPA has 99 MPs in the Upper House and the opposition has about 131.
If the SP and BSP abstain from voting in Rajya Sabha on the lokpal bill - as they did in Lok Sabha on Tuesday - the government stands in with a chance to get the legislation passed, but with a wafer-thin majority.
The government does not seem to have the numbers in the Upper House if the two Uttar Pradesh parties join hands with the opposition parties led by the BJP and the Left on key amendments.
Such a scenario would see the bill falling in Rajya Sabha or passing with amendments that would be in conflict with the clauses of the bill passed by Lok Sabha.
A fallen bill in Rajya Sabha would imply either a joint session to get it passed, or reconsideration of the amendments by Lok Sabha, or the bill going into cold storage like the women's reservation bill.
The BJP had been counting on finding common ground with the Left, SP and BSP on some amendments, but the SP and BSP's walkout in Lok Sabha threatens to pour cold water on its plans.
"We are trying to make common cause with the Left, SP and BSP on some key amendments, including an independent CBI, safeguarding MPs, making lokayuktas optional for states in the interest of the federal structure, broad basing the selection of the CBI director among other issues," a BJP leader said on Tuesday.
"We are also convincing ally Shiv Sena, anyway opposed to the lokpal, to vote with us on our amendments."
An abstention by the SP and BSP, the leader feared, would mean the bill might pass.