Pakistan's under-fire government faces a day of legal challenges on Monday, with two court hearings that could pave the way to unseating the leadership and forcing early elections.

Supreme Court judges are to hear a long-running Swiss corruption case chiefly against President Asif Ali Zardari as a high court commission probes the scandal that has become known as "Memogate".

The memo case centres on an unsigned note allegedly sent by an aide of Zardari to the US military last May, seeking help in stopping a possible coup following the covert killing of Osama bin Laden in Pakistan by US Navy SEALs.

The commission, set up on December 30 following a demand from the country's top intelligence officer, is to hear from the government on Monday and should return its findings later in the month on whether Islamabad endorsed the note.

On Monday, the attorney general said the commission had not obtained crucial evidence -- Blackberry message data sent between Zardari's aide, then-ambassador to Washington Husain Haqqani, and US businessman Mansoor Ijaz.

Ijaz first made the memo scandal public in a newspaper piece published in October, in which he claimed to have acted as a go-between. Haqqani denies any involvement in the note and says that Ijaz invented the entire story.

"Blackberry company has not provided the data," Attorney General Maulvi Anwarul Haq told reporters at Islamabad High Court. "And we have no information about Mansoor Ijaz."

The Supreme Court will also meet to decide how to proceed on graft charges against Zardari and other lawmakers, who claim to have amnesty from prosecution in the case.

After a smaller panel of judges failed to reach a decision last week, a larger bench will convene to debate six options, which include dismissing the prime minister and holding early elections.

In the afternoon the National Assembly, the country's legislative body, is to vote on a resolution tabled by a minor coalition party in a bid to bolster the civilian leadership amid a simmering row with the powerful army.

Tensions between civilian leaders and the army reached fever pitch last week when Prime Minister Yousuf Raza Gilani accused the military of failing to submit statements to the memo commission through government channels and later sacked his defence secretary who was considered close to the generals.

The army issued a terse statement that warned of "potential grievous consequences for the country" and the row provoked fears of another coup in the country that has spent half its existence under military rule.

But political and defence analysts believe that the military has no appetite for a coup and would prefer to see the leaders removed by legal means.

Gilani moved over the weekend to calm mounting tensions, praising the military's role in a meeting of the cabinet defence committee.

"The armed forces of Pakistan are a pillar of the nation's resilience and strength. The nation applauds their heroic services in the defence of the motherland," he said.

The meeting, in which Gilani called for national unity, was attended by army chief General Ashfaq Kayani, widely regarded as Pakistan's most powerful figure, as well as several other top military officials.