The move is a blow to the pro-democracy movement that toppled the long-time president, himself derided by many as a pharaoh.
Opposition forces denounced the declaration as a "coup" and called for nationwide protests on Friday.
"The president can issue any decision or measure to protect the revolution," according to a decree read out on television by presidential spokesman Yasser Ali.
"The constitutional declarations, decisions and laws issued by the president are final and not subject to appeal."
"This is a coup against legitimacy... We are calling on all Egyptians to protest in all of Egypt's squares on Friday," said Sameh Ashour, head of the Lawyers syndicate, in a joint news conference with leading dissidents Mohamed ElBaradei and Amr Mussa.
They accused Morsi of "monopolising all three branches of government" and of overseeing "the total execution of the independence of the judiciary."
Nobel laureate and former UN atomic energy agency chief ElBaradei had earlier lashed out at the declaration, which would effectively put the president above judicial oversight.
"Morsi today usurped all state powers and appointed himself Egypt's new pharaoh. A major blow to the revolution that could have dire consequences," ElBaradei wrote on his Twitter account.
The head of the influential Judge's Club, Ahmed al-Zind, told a press conference that the judges would hold an emergency meeting on Saturday to decide on their next step, promising "actions, not words."
Morsi also sacked prosecutor general Abdel Meguid Mahmud, whom he failed to oust last month amid strong misgivings among the president's supporters about the failure to secure convictions of more members of the old regime.
He appointed Talaat Ibrahim Abdallah to replace Mahmud and, within minutes of the announcement, the new prosecutor was shown on television being sworn in.
Abdullah later issued a brief statement on state television, pledging to "work day and night to achieve the goals of the revolution."
In his pronouncement, the president also ordered "new investigations and retrials" in the cases dealing with the deaths of protesters, a decision that could net senior military officials and see Mubarak reinvestigated.
He also said no judicial body can dissolve the upper house of parliament or the constituent assembly that is writing a new constitution and which has been criticised by the secular-minded opposition for failing to represent all segments of society.
The declaration is aimed at "cleansing state institutions" and "destroying the infrastructure of the old regime," the president's spokesman said.
Ali said Morsi had issued a new law, which is yet to be ratified by the new parliament, calling for the creation of a "revolutionary prosecution" to investigate crimes related to the killing of protesters and to hold accountable anyone who withheld evidence in previous trials.
A senior official with the Justice and Freedom Party, the Muslim Brotherhood's political arm, said the move was necessary to guarantee the revolution was on course.
"We could not find any legal avenue to pinpoint and prosecute those in the ministry of interior who were responsible for killings," Gehad Haddad told AFP.
He said there had been a string of acquittals of interior ministry officials, evidence was withheld in cases, investigations had been weak and many had not been brought to trial over the killings of hundreds of protesters during and since the uprising - a view that secular protesters would agree with.
"The avenues we are taking are born of necessity, not choice," he said.
Heba Morayef, Egypt Director at Human Rights Watch, welcomed the retrials but criticised aspects of the declaration.
"What's fundamentally problematic and threatens both the rule of law and overall democratic checks and balances is his decision to give his decrees immunity from the judiciary until the constitution is passed," Morayef told AFP.
"As a judge, I feel paralysed," one judge at Egypt's State Council told AFP.
Even before the announcement was read out, fundamentalists had gathered outside the High Court in central Cairo demanding the "cleansing of the judiciary."
They "will bring justice to the martyrs and will hold the corrupt accountable," said Mahmud Sultan.
But a few kilometres (miles) away, there were vocal denunciations of Morsi's declaration.
"We didn't have an uprising so that we put in place another dictator," said a furious Khaled Ali. "He's not just a pharaoh, he thinks he's God."
Morsi, who hails from the powerful Muslim Brotherhood, is the first president to be elected since Mubarak stepped down. He is also the country's first civilian head of state.
COMMENTS (20)
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@MK: This was useful information. Thank you.
Muslim nations can NEVER have true democracy. Even Turkey is just a temporary phenomena. Watch for the generals to take control in the future. There is something in the DNA of Muslims that encourages autocrats and dictators.
@MK:
No president is allowed extra-constitutional steps like Mursi the dictator is doing, no matter what pathetic excuse you try to come up with.
@Umer:
Zardari is head of state, not Government. Zardari is already interfering more than he should in government affairs. I assume you do not have a clear idea of how a presidential system (as in US and Egypt) and a British style Parliamentary system (India and Pakistan) work. Presenting Zardari as an example and comparing his role with a president of Egypt explains your lack of understanding of the two systems. You can compare Zardari with president if India, How often do you see Indian President making policy decisions.But you see President of US running the show in US. BECAUSE!!! they have PRESIDENTIAL!!! system in US and so does Egypt.
@MK:
Zardari is also elected president but we don’t allow him to subvert the court extra-constitutionally. You have a very twisted idea of being elected. You are confusing a democratic election with dictatorship.
Cat is out of the bag. Islamists use democracy only so they can come into power and then become dictators. Egyptian people made a mistake and now they are going to pay for it for years to come.
Middle east and islamic country's real destiny....what's new in it ?
Many people commenting here have absolutely no idea of the back ground of the events. They sole information source about the situation in Egypt is probably this article. Article is a collection of statements from both sides but title and composition presents a anti Mursi tone.
There were two elections after Mubarak. One to choose representatives in the assembly and second for the president in Egypt. Muslim brotherhood came ahead of in both but NOT with a big margin. Country was ruled by a military council headed by Field Marshal Tantawi. Both chiefs of judiciary and army were chosen and were allies of 32 year Mubarak dictatorship and tried their best not to hand over real power to elected reps and President. Military ruled to keep certain ministries to themselves and a veto power on many decisions. ELECTED President moved in and asserted his power by not extending the military chief tenure and replacing army chief with next in command. He made him a defense adviser instead. Notice he did not choose an Islamist because there were none at high posts in the military, During protests in Tahrir square Mubarak sent goons on camels to break up protests when army refused to fire on protesters. These guys showed up on camels with knives swords and sticks and injured and killed hundreds (all caught on camera). So these people were put on trial they all got acquitted (YES not a single was found guilty) because the prosecution (still from Mubarak Era with loyalties to him) did not bring about any credible evidence against them. So Mursi replaced him (Same as US president appoints a Prosecutor General in US) . All those were selected by dictatorship and are still loyal to Mubarak and are used to old DICTATORSHIP ways. Instead of removing every head of institute at once he is taking slow steps allowing establishment and judiciary to adapt to democracy, and avoiding a total chaos Iraq is a clear example where all government departments and military from Saddam was abolished and country descended in to chaos. Dictatorship era judiciary wanted to suspend ELECTED assembly and prevent it from functioning. A council and an ELECTED I REPEAT ELECTED assembly is tasked to formulate a new constitution. But that is not all, that constitution is then going to be put for a referendum for all Egyptians to vote on before it is made a law. So Mursi is trying to assert his democratic authority, bring criminals to justice, bring army under civilian control, and make a new constitution to present it to the PEOPLE of EGYPT who will have all the chance to REJECT it if they do not like it. Please let him work and do his job. Since Egypt is a democracy now, people can replace him in next elections if they do not like him (Unlike Mubarak who ruled for 32 years). Muslim brotherhood contested elections and won in Egypt and Tunisia but lost in Libya. They are not dictators. They run schools and hospitals in Egypt and in other parts of Arab world. They have strong roots in the society. Secular democratic parties who were part of the protests and contested elections lost because they are not very organized and segmented which divided secular vote. Maybe next time for them (at least under Mursi one can expect a NEXT time in 4 years), but do not undermine an ELECTED parliament and President who are trying to do their job. Egypt is an ancient civilization and just got its FIRST CIVILIAN president. Democracy is in it's infancy there and he is trying to work with Dictatorship Era heads of departments.
In Egypt, just like Pakistan, establishment has been very strong historically and status quo is well entrenched. This seems like an attempt on his part to short-cut the process of change, which is understandable, but is prone to abuse in the long run.
pharaoh is not applicable for a islamic civilization . Gone are those days when Misr used to have a golden culture . That culture has been ruined by the prevailing culture of Arab and middle east.
I think it is a bold step to cleanout the dirt of the ex dictator. It is a good step to clean the secular and corrput Judiciary, administration and the Army.
The people who are making comments here must read the history how Judiciary made a verdict against the new elected parliament?
I hope Mr. Morsi for the best. Mr. Morsi Keep it up.
what else one can expect out of Arab nations? And Pakistan wants to ape them- disowning their true heritage.
One man, one vote, one time. The path of religious political parties in Muslim world
Farid ZakariaReminiscent of Iran - kick out a secular dictator and replace him with an Islamic dictator. So much for the Arab Spring.
Hopefully he'll be ousted by 2042 when the planet would be ruled by apes. Oh wait, that is actually true about Pakistan.
Out of the frying pan and into the fire for the poor people of Egypt.
this is the inevitable fate of the Islamic nations.
That was not wholly unexpected. Religious leaders are not fond of ruling democratically.
Bring down Morsi