NEW DELHI: The NDA and the opposition on Monday appeared to be heading for a showdown in the Rajya Sabha for election to the deputy chairman 's post with JD(U) MP Harivansh emerging as the ruling alliance's candidate and the opposition giving a clear indication of fighting the August 9 contest. 

Hours after Rajya Sabha chairman M Venkaiah Naidu announced the date for election to the post, almost all opposition parties held a meeting where they decided to field a common candidate for the contest in the Upper House, where the BJP-led ruling alliance lacks majority. 

A senior leader who attended the deliberations said all those present were told to discuss the issue within their respective parties and come up with suggestions for a common candidate when the opposition meets again tomorrow.  It is learnt that the Congress was open to supporting a nominee from any opposition party. 

According to opposition sources, Tiruchi Siva of DMK, Vandana Chavan of NCP and nominated member KTS Tulsi are the front runners for the post. 

While the BJP-led NDA did not make any formal announcement, sources said Harivansh, a first time parliamentarian, is likely to be their choice for the post. 

The Opposition has often prevailed on the government in the numbers game in the House but the BJP is hopeful that it can get the better of its rivals with the support of regional parties like the AIADMK, BJD, TRS and YSR Congress- all of whom have lent support to it now and then. 

Rajya Sabha chairman M Venkaiah Naidu announced in the House that the election will be held at 11am on August 9. 

He also suggested that the deputy chairman should be elected by consensus.  The nomination papers will have to be filed before noon on August 8. 

The post of the deputy chairman has been lying vacant since June this year following the retirement of PJ Kurien, who had been elected to the Upper House of Parliament on a Congress ticket from Kerala. 

The BJP's decision to opt for a member of its ally as its choice is driven by its desire to be more accommodative to its partners, many of whom have often expressed their reservations at the treatment meted out to them by the saffron party since the government was formed in 2014. 

The current strength of the Rajya Sabha is 244 and support of 123 members would be needed for a win in the full House. 

The BJP is the largest party in the House with 73 members.  Its allies JD(U), Shiv Sena, Akali Dal have 6, 3, 3. 

Besides the nominated and independent members affiliated to it, the BJP is banking on the support of 13, nine, six and two members of the AIADMK, BJD, TRS, YSR Congress respectively, its floor managers said. 

If all four parties support the NDA candidate, then the numbers add up to 126. 

However, if parties like BJD or TRS abstain from voting, then things will become more precarious for the ruling alliance. 

Both these parties had abstained during a vote on the recent motion of no-confidence against the government in the Lok Sabha while the AIADMK had voted with the treasury benches. 

The BJP is hoping to get support of four of the six Independent members and three of the four nominated members. 

The Congress has 50 members.