Prime Minister Atal Behari Vajpayee's Hindu nationalist Bharatiya Janata Party (BJP) is expected to improve its tally from the 182 seats it scooped in 1999 to about 200, according to a poll conducted last week by Delhi-based C-Voter agency.

However, this is far short of the 272 seats needed in the 545-seat lower house of parliament -- where two nominated members have no voting rights -- to be able to form a government.

Adding seats expected to be won by the BJP's coalition partners in the National Democratic Alliance (NDA), the figure jumps to around 260-263 seats, according to the poll.

The main opposition Congress party is expected to get 110-120 seats and its allies another 70, while a "third force" of non-aligned parties may get around 100 seats, according to the poll, conducted among 12,000 people in 120 constituencies.

"Increasingly the trends are showing that there is a distinct possibility of the NDA getting less than the required majority," said Yashwanmt Deshmukh of C-Voter.

"Slowly and slowly they are going down. It's a very, very tight situation. The third force has to be closely watched. They could make or break any alliance," he added.

At the start of the campaign for the polls which begin April 20, most opinion polls predicted a clear win for Vajpayee's ruling coalition.

The most prominent poll, conducted jointly by NDTV channel, Indian Express newspaper and A.C. Nielson agency and released March 26, gave 287 to 307 seats to the NDA and 143 to 163 to Congress and its allies.

Several subsequent polls have shown a dip in the NDA's winning margins, with one predicting the coalition may fail to secure a majority.