The Egyptian Judges Club, a union with 9,500 members, has said judges would not, as customary, oversee the national referendum called for 15 December.

Egyptian President Mohammed Mursi called the referendum on a draft constitution hammered out and hurriedly voted on last week.

"We have decided to boycott the supervision on the constitution referendum until this decree is rescinded," Judge Ahmed al-Zend, head of the club, said.

The absence of the Judges Club's oversight would raise more questions about the validity of the vote.

If the draft is passed in the referendum, parliamentary elections are to follow two months later and they too may not have judicial supervision.

The judges say they will remain on strike until Mr Mursi rescinds his decrees, which the Egyptian leader said were temporary and needed to protect the nation's path to democratic rule.

Egypt's rebellion of the judges against Mr Mursi became complete with the country's highest court declaring an open-ended strike on the day it was supposed to rule on the legitimacy of two key assemblies controlled by allies of the Islamist leader.

The strike by the Supreme Constitutional Court and opposition plans to march on the presidential palace tomorrow take the country's latest political crisis to a level not seen in the nearly two years of turmoil since former president Hosni Mubarak's ouster in a popular uprising.

Judges from the country's highest appeals court and its sister lower court were already on an indefinite strike, joining colleagues from other tribunals who suspended work last week to protest what they saw as Mr Mursi's assault on the judiciary.