Corruption cases have been opened against senior politicians
A bench of Pakistan's Supreme Court is due to hear appeals from politicians after it lifted an amnesty for politicians facing graft charges.
The three-member bench headed by Chief Justice Iftikhar Chaudhry will begin hearing the appeals on Monday.
Senior figures, including interior and defence ministers, are among those affected by the Supreme Court ruling.
The controversial law granting senior politicians amnesty was brought in by former President Pervez Musharraf.
The court's move last week opened the way for possible prosecution for President Asif Zardari's political allies, although he is still protected by presidential immunity.
Pakistani ministers have said they will not resign following the court ruling.
Interior Minister Rehman Malik said the government had no intention of bowing to opposition demands to stand down.
Mr Malik is one of around 250 officials whose corruption and criminal cases have been re-opened - he has received a summons to appear before an anti-corruption court since that amnesty was overturned.
President Zardari has been holding crisis talks with party leaders.
Correspondents say that while the government officials affected, including President Zardari himself, are legally able to remain in power, the question over whether they should morally stay there with the cloud of corruption hanging over them is not going away.
The amnesty was introduced by Mr Musharraf in order to allow Mr Zardari's late wife, Benazir Bhutto, to return to the country and stand for office, with the aim of a possible power-sharing deal with Mr Musharraf.
She returned to Pakistan from abroad after the so-called National Reconciliation Ordinance was signed into law, but was assassinated soon after.