In a new twist, the Pakistan Muslim  League-N has apparently linked its cooperation with Pakistan People's Party for forming a coalition government to withdrawal of a ban on a third prime ministerial term for former premier Nawaz Sharif.

The law was passed by President Pervez Musharraf [Images] in 2002 to bar Sharif and PPP leader Benazir Bhutto [Images], both two-time prime ministers, from occupying the top slot again.

Before cooperating with the PPP, the PML-N will seek a guarantee that after coming to power, the PPP-led government will withdraw the amendment to the Constitution that bars a third prime ministerial term, sources told the Daily Times newspaper.

Sharif and PPP co-chairman Asif Ali Zardari had announced they would join hands to form governments at the Centre and in the provinces after their parties emerged the two largest groups in the National Assembly in the February 18 general election.

Sources said the PML-N would try to woo the Awami National Party, which emerged the largest group in the North West Frontier Province, and other parties to ensure that the bar on a third prime ministerial term is withdrawn at the earliest.

However, a leader of Musharraf-backed PML-Q said his party would oppose any amendment to allow Sharif to contest for premiership again.

Sharif can become prime minister again only with the prior consent of the President through a bill passed by parliament with a simple majority.

"It does not require two-thirds majority to allow him to become a prime minister for the third time," the unnamed PML-Q leader said.