Zaffar Abbas BBC correspondent in Islamabad

Pakistan's Supreme Court has overturned an order by President Pervez Musharraf that barred candidates who lost in October's national and provincial assembly elections from standing in Senate polls.

The court said the decree was discriminatory and unconstitutional.

The ruling comes just two weeks before the Senate elections.

Several politicians had filed petitions asking the court to allow them to contest the polls for the upper house of parliament.

Consequences

The court's bench, headed by the chief justice, said a detailed judgement would be released later.

The court had earlier upheld as valid a number of other decrees issued by President Musharraf to change election procedures.

The court backed previous Musharraf decrees

The judges indicated that the changes governing Senate elections should have been made before the national and provincial assembly polls, so the participants would have known the consequences of defeat.

It was thus unfair to bar the losers, the court ruled.

In its brief order, the Supreme Court did not touch upon the crucial question concerning the amendments President Musharraf made to the constitution before calling the parliamentary elections.

The amendment package, known as the Legal Framework Order, is the real bone of contention between the government and opposition.

Most lawyers' associations side with the opposition and say the order cannot become part of the constitution unless it wins a two-thirds majority in parliament.

A verdict by the Supreme Court on the status of the order will be crucial for the future of the country's parliamentary system.