Pakistan on Tuesday plunged into a fresh spell of political uncertainty after the Supreme Court ruled that Prime Minister Yousuf Raza Gilani stood disqualified since his conviction for contempt and asked President Asif Ali Zardari to appoint a new premier.

A three-judge bench headed by Chief Justice Iftikhar Chaudhry issued the verdict in response to several petitions that had challenged National Assembly Speaker Fehmida Mirza's decision not to disqualify Gilani following his conviction nearly two months ago.

The bench further ruled that the post of premier had been vacant since April 26, when another seven-judge bench had convicted Gilani of contempt for refusing to reopen graft cases in Switzerland against President Zardari.

The bench directed the Election Commission to issue a notification stating that Gilani, 60, was no longer a member of Parliament.

In response to a demand from a petitioner that the court should direct the President to order the election of a new premier, the bench asked Zardari to act according to the Constitution for the continuation of democracy.

The apex court's ruling had been expected in political circles for some time.

During the hearing of the petitions yesterday, the Chief Justice had questioned whether a convicted person could continue representing the 180 million people of Pakistan.

The judiciary and the government have been engaged in a standoff since December 2009, when the apex court annulled a graft amnesty issued by former military ruler Pervez Musharraf that benefited Zardari and over 8,000 others.

Since then, the judiciary has been pressuring the government to reopen the corruption cases against Zardari.

The government refused to act, saying the President enjoyed immunity from prosecution in Pakistan and abroad.

Matters reached a head when the apex court charged Gilani with contempt for refusing to act on its orders earlier this year.

Gilani was convicted and given a symbolic sentence of less than a minute on April 26.

Gilani refused to resign even though the apex court had said at the time that his conviction could lead to his disqualification.

The Speaker last month ruled out the disqualification of Gilani following his conviction, saying he had not been charged with acting in a manner prejudicial to the integrity or independence of the judiciary.

Earlier in the day, the Chief Justice questioned whether the Speaker could scrutinise the judgement of a seven-judge bench of the apex court.

However, the crusading Chief Justice has come under a cloud following real estate tycoon Malik Riaz Hussain's acknowledgement that he paid Rs 342.5 million to the top judge's son Arsalan Iftikhar to influence cases in the apex court.

Despite enjoying the support of lawyers across the country, the Chief Justice has been accused by legal experts of acting in a biased manner against the ruling Pakistan People's Party and especially President Zardari.

In a related development, the top leadership of the PPP gathered in the presidency for an emergency meeting chaired by Zardari, the co-chairman of the party, and his son, party chairman Bilawal Bhutto Zardari.

The meeting discussed the options available to the government following the apex court's ruling, sources said.