The biennial elections for five Rajya Sabha seats from West Bengal began in Kolkata Tuesday morning as six candidates put up fight for berths in the Upper House.

With the Congress putting up the sixth candidate despite lagging in the number game, an undercurrent of curiosity prevails over the possibility of cross voting that the party banks on.

With five seats remaining vacant in a House of 294, altogether 289 members will cast their votes.

While the Left Front has put up four candidates -- Saman Pathak (Communist Party of India-Marxist), Mainul Hasan(CPI-M), Tapan Sen (CPI-M) and Dr Barun Mukherjee (Forward Bloc) -- Mukul Roy and Subrata Mukherjee are the nominees of the Trinamool Congress and Congress respectively.

The elections are being held for the seats, held by Nilotpal Basu and Dipankar Mukherjee of the CPI-M, Manoj Bhattacharya of the Revolutionary Socialist Party and Jayanta Bhattacharya of the Congress, whose terms are set to expire. The fifth seat fell vacant following the death of Biplab Dasgupta of the CPI-M.

While all the four Left candidates and the lone Trinamool nominee were certain to get elected to the Upper House, the entry of former mayor Subrata Mukherjee in the fray made things interesting.

In the present House, the Congress has a strength of 26 besides having the support of four independents, while the Trinamool has 53 legislators and the ruling Left Front 196.

Even though the Congress can garner a maximum of 41 votes in its favour having the support of three Gorkha National Liberation Front legislators, four MLAs who quit the Trinamool, two of the dissident Forward Bloc and two other expelled MLAs from the Front, it falls short of eight votes from the required number to get its candidate elected.

With the Trinamool Congress issuing a whip against casting even the five extra votes the party had in favour of Mukherjee, the Congress now heavily banks on making up for the deficit from the Left vote. The party claims that it would get the support of the Left MLAs who had not been given nomination for the coming Assembly elections.

The polling will continue till 1600 hours.