Supreme Constitutional Court in Egypt, which dissolved the parliament last month, is due to discuss how to respond to President Mohammed Mursi’s order to reconvene it.
The speaker of the dissolved house has called for it to meet on Tuesday.
Military and judicial authorities have held emergency talks, but have not announced any action so far.
Mohammed Mursi, whose Muslim Brotherhood won most seats, said the chamber should reconvene until a new election is held.
Military police are keeping the area around the parliament building sealed.
Egypt’s Supreme Constitutional Court is due to discuss how to respond to President Mohammed Mursi's order to reconvene parliament dissolution
It is not clear when or how MPs are expected to reconvene.
MPs would first have to get past a line of police and military guards who have been preventing them from entering the parliament building – or they could meet elsewhere.
The Supreme Council of the Armed Forces (SCAF) – which has assumed legislative power – met in an emergency session shortly after the presidential decree was issued on Sunday.
It is due to hold another meeting.
The military had enforced a court order last month dissolving parliament because party members had contested seats reserved for independents.
The SCAF took over the reins of power last year, after the revolution that ended former President Hosni Mubarak’s 30-year rule.
The army move was initially welcomed by many of the anti-government protesters, but its presence became increasingly unpopular as critics accused its leaders of wanting to hold on to power.
Mohammed Mursi won the country’s first free presidential election last month, and army chiefs formally handed over power on 30 June.
But before his inauguration, the military had granted itself sweeping powers.
The commanders’ constitutional declaration stripped the president of any authority over the military, gave military chiefs legislative powers, and the power to veto the new constitution, which has yet to be drafted.
In his presidential decree, Mohammed Mursi said new parliamentary elections would be held 60 days after the constitution had been agreed by referendum, the decree said.
The Muslim Brotherhood has consistently opposed the decision to dissolve parliament.
But analysts say it is unclear whether the president has the authority to reinstate the assembly.
If there was a political truce in Egypt, it could soon be over – unless this is part of a more complicated deal, under which parliament would meet briefly then be dissolved by the president.
Bloomberg: Egypt’s President Mohamed Mursi Reinstates Parliament
Egyptians are set to vote in the second round of their first free presidential election in a two-day run-off.
Mohammed Mursi, head of the Muslim Brotherhood’s Freedom and Justice Party, is up against Ahmed Shafiq, Hosni Mubarak’s last prime minister.
The ruling Supreme Council of the Armed Forces has promised to hand over power to the winner by 1 July at the latest.
But the build-up to the election has been marred by a Supreme Constitutional Court decision to dissolve parliament.
On Thursday, a panel of judges – appointed by Hosni Mubarak – ruled that the law governing Egypt’s first democratic elections in more than six decades was unconstitutional because party members were allowed to contest seats reserved for independents.
The Freedom and Justice Party won about 100 of its 235 seats in the People’s Assembly by running candidates for individual seats.
If parliament is dissolved swiftly by the ruling Supreme Council of the Armed Forces (SCAF), whoever wins this weekend’s presidential run-off could take office without the oversight of a sitting parliament, and without a permanent constitution to define his powers or duties.
A 100-member assembly appointed by parliament earlier this week to draft the new constitution may also be dissolved.
Islamist, liberals and scholars denounced the ruling as a “coup”, saying they feared the ruling generals would take back legislative power.
“This series of measures shows that the Supreme Council of the Armed Forces, the head of the counter-revolution, is adamant to bring back the old regime and the presidential elections are merely a show,” six parties and movements said in a joint statement that also urged Mohammed Mursi to boycott the run-off.
The Supreme Constitutional Court also found a law blocking senior Mubarak-era officials from the presidency – which would have ruled out Ahmed Shafiq’s candidacy – was unconstitutional. The law was passed by parliament before the presidential election’s first round.
On Friday, the Muslim Brotherhood vowed to win the presidency despite the signs of opposition within the judiciary, which is overseeing the vote.
“Isolate the representative of the former regime through the ballot box,” said a statement referring to Ahmed Shafiq, who also served as head of the air force and minister of aviation under Hosni Mubarak.
The Brotherhood warned that the progress made since the president was forced to step down was being “wiped out and overturned”.
Egypt was facing a situation that was “even more dangerous than that in the final days of Mubarak’s rule,” the group added.
Mohammed Mursi meanwhile sought to reassure the military and its supporters within the electorate that he would work closely with the generals.
“As president, they will be in my heart and will get my attention… they will never do anything to harm the nation,” he said.
On Thursday, Mohammed Mursi warned there would be a “huge revolution against the criminals” if there was any evidence of electoral fraud.
His opponent meanwhile told a rally that the court rulings were “historic” and that the “era of political score-settling” had ended.
On Friday, Ahmed Shafiq promised to “address chaos and return stability”.
He came second in last month’s first round, in which turnout among the 52 million eligible voters was only 46%. Official results gave Mohammed Mursi 24.8% and Ahmed Shafiq 23.7%.
Polling stations are due to open on Saturday and Sunday at 08:00 and close at 19:00, but voting is likely to be extended on both days.
Final results from the Higher Presidential Election Commission (HPEC) are due by 21 June, but are expected to arrive much earlier.
Partial results from the first round were declared within 24 hours.
US Secretary of State Hillary Clinton has called for the SCAF to transfer power fully to a democratically elected civilian administration as soon as possible following the announcement of the final result of the election.
“There can be no going back on the democratic transition called for by the Egyptian people,” she told reporters in Washington.
Egyptians are starting to vote in their first free presidential election, 15 months after ousting Hosni Mubarak in the Arab Spring uprising.
Fifty million people are eligible to vote, and queues are forming at some polling stations.
The military council which assumed presidential power in February 2011 has promised a fair vote and civilian rule.
The election pits Islamists against secularists, and revolutionaries against Mubarak-era ministers.
The frontrunners are:
• Ahmed Shafiq, a former commander of the air force and briefly prime minister during February 2011 protests
• Amr Moussa, who has served as foreign minister and head of the Arab League
• Mohammed Mursi, who heads Muslim Brotherhood’s Freedom and Justice Party
• Abdul Moneim Aboul Fotouh, an independent Islamist candidate.
Egyptians are starting to vote in their first free presidential election, 15 months after ousting Hosni Mubarak in the Arab Spring uprising
Until a new constitution is approved it is unclear what powers the president will have, prompting fears of friction with the military.
Voting began promptly at 08:00 local time, with queues observed at many Cairo polling stations growing longer by the minute.
“It’s a very big day,” said one woman. “This is a real great moment for the Egyptians to change.”
Another, when asked how long she had been waiting to vote, replied, with a laugh: “30 years.”
One man said it was most important for the new president to have his own programme.
“Actually he has to be in the revolution, or he has to be a strong part in the revolution. This is something which is not negotiable,” he said.
Mohammed Mursi was originally the Muslim Brotherhood’s reserve candidate, but he was thrust into the limelight after its first choice, Khairat al-Shater, was disqualified by the Higher Presidential Electoral Commission (HPEC) over an unresolved conviction.
The Brotherhood have nevertheless likened Mohammed Mursi, a US-educated engineer and MP, to an underrated football substitute.
“In any match there is the reserve who plays in the last 10 minutes, scores the goal and wins the match. Mursi is our reserve player,” said cleric Mohamed Abdel Maqsoud while addressing a crowd of Brotherhood supporters on Sunday.
A run-off vote is scheduled for 16 and 17 June if there is no outright winner.
There is also a potential clash waiting to happen with the military, which seems determined to retain its position as the power behind the president’s chair.
And the electorate does not know what powers the new president will have to do his job, as they are still waiting for them to be spelled out in a new constitution.
The election is being hailed as a landmark for Egyptians, who have the opportunity to choose their leader for the first time in the country’s 5,000-year recorded history.
The Supreme Council of the Armed Forces (SCAF), worried about potential post-election unrest, has sought to reassure Egyptians that it will be the voters themselves who decide who will be the next president.
“It is important that we all accept the election results, which will reflect the free choice of the Egyptian people, bearing in mind that Egypt’s democratic process is taking its first step and we all must contribute to its success,” it said in a statement on Monday.
The 15 months since Hosni Mubarak was forced from power has been turbulent, with continued violent protests and a deteriorating economy.
Foreign direct investment has reversed from $6.4 billion flowing into the country in 2010 to $500 million leaving it last year.
Tourism, a major revenue generator for the country, has also dropped by a third.
The new president will also have to reform the police to deal with the rash of crime that followed the uprising.
As many as a third of voters are reported to be undecided about which candidate to choose.
The Arab Spring began in Tunisia last year when weeks of protests forced President Zine al-Abidine Ben Ali from power, inspiring pro-democracy activists across the Arab world.
Egyptian President Hosni Mubarak, in power for three decades, resigned on 11 February 2011 after 18 days of protests in Cairo and other cities.
Hosni Mubarak is on trial for his alleged role in the deaths of protesters, and a verdict in the case is due on 2 June.