The Bharatiya Janata Party, which heads the National Democratic Alliance, on Monday said it would not join hands with the Ramvilas Paswan-led Lok Janshakti Party in case of a hung assembly in Bihar.

"Though a pro-NDA wave seems to be sweeping across Bihar and I am reasonably sure about forming our government, we will prefer to sit in opposition in the event of a fractured mandate rather than join hands with Paswan," BJP general secretary Pramod Mahajan said.

An NDA victory would weaken the United Progressive Alliance government, he said, adding that if Lalu Prasad returned to power, he would "blackmail" the Union government.

"In both situations, the central government is in for a major headache," Mahajan said. "The Left parties are already dissatisfied with the Congress-led UPA government and Prasad's failure to secure a fourth term will weaken the ruling coalition," he said.

He said Janata Dal-United chief Nitish Kumar was the NDA's chief ministerial candidate.

Asked if the BJP would go back on its word if it won more seats than the JD-U, Mahajan said, "While BJP has fielded 103 candidates, JD-U has put up 138, and so we expect it to win larger number of seats. In such a situation Nitish Kumar will be the natural choice."