Pakistan's embattled civilian government faces a day of legal challengers, amid an ongoing crisis with the powerful military.
The Supreme Court and a commission will hold hearings, which could pave the way to unseat Yousuf Raza Gilani's cabinet.
Separately, a vote of confidence in the government is expected later in the day in the country's parliament.
Prime Minister Gilani says conspirators are plotting to bring down his cabinet, without specifically blaming the army.
However, correspondents say that things appear to have calmed down since this weekend's talks between the civilian and military elites, during which Mr Gilani described the armed forces as "a pillar of the nation's resilience and strength".
Pakistan has suffered three military coups since independence in 1947.
On Monday, the Supreme Court is due to hold a hearing into the implementation of its recent order annulling a controversial amnesty law, which had protected the country's senior politicians.
A court deadline for the government to reopen cases of political corruption - including the one against President Asif Ali Zardari by the Swiss authorities - expires on Monday.
The government has so far refused to comply, but last week the court ordered government representatives to appear at the hearing to explain what they planned to do.
Separately, a commission will hear from the government on a high-profile investigation into the so-called "memogate" scandal.
The rift began with an anonymous memo apparently seeking help from the US to avert a possible military coup following the killing by US forces of al-Qaeda leader Osama Bin Laden last May.
It is not clear who wrote the memo or conveyed it to Washington. US officials say they received the memo but took no action.
The commission, set up last month, is expected to question government officials to try to establish whether they endorsed the memo, and if so, whether the cabinet can remain in power.
The findings of the investigation are due to be announced later this month.
Also on Monday, a vote of confidence in Mr Gilani's cabinet will be held in parliament.
Correspondents says the prime minister is likely to win the backing, and that lawmakers' seal of approval will probably to strengthen his hand.