Egypt's most senior judges have agreed to supervise a December 15 referendum on a new constitution drafted primarily by Islamists, giving a boost to President Mohammed Morsi, who called the vote.

The Supreme Judicial Council Monday said it will delegate officials to oversee the referendum, rejecting a call by lower-ranked judges with the influential Judges Club for a boycott. The Judges Club issued a statement Sunday urging a boycott as a protest against Mr. Morsi's November 22 decree that bars any courts from challenging his decisions.

President Morsi needs judicial supervision of the referendum to legitimize it and the constitution drafted by his allies in a constituent assembly, which handed him the document on Saturday. Officials said they were moving ahead with referendum plans, including arrangements for Egyptian expatriates to cast their ballots at diplomatic missions abroad.

Mr. Morsi's liberal and secular opponents, including many junior judges, want to delegitimize the constitutional referendum by refusing to participate. They accuse the Islamist-dominated constituent assembly of drafting a charter that would threaten civil liberties by imposing a stricter interpretation of Islam. Liberals and Christians boycotted the constitution-drafting process.

An opposition coalition is planning a march to President Morsi's Cairo office Tuesday to denounce his planned referendum and demand that he scrap the decree that granted him what they see as near-dictatorial powers. Mr. Morsi has promised to lift the decree once the public approves a new constitution in a referendum.

Several independent Egyptian newspapers said they will join the protest by refusing to print their Tuesday editions.

Adding to the sense of crisis, Egypt's top court began an indefinite strike on Sunday, joining other courts that stopped work in recent days due to what they see as Mr. Morsi's assault on the judiciary. The judges of the Supreme Constitutional Court said they were afraid to approach their offices because thousands of Islamists had massed outside.

The top court had been due to issue rulings that could have dissolved the constituent assembly and the upper house of parliament, also controlled by Islamists. The court's Islamist critics say it is biased against them because its judges were appointed by Hosni Mubarak, a longtime anti-Islamist president who was ousted last year in a popular uprising.