The Judges Club, a union with 9,500 members, said late Sunday that judges would not, as customary, oversee the national referendum Morsi called for Dec. 15 on the draft constitution hammered out and hurriedly voted on last week.
The absence of their 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 Morsi rescinds his decrees, which the Egyptian leader said were temporary and needed to protect the nation's path to democratic rule.
For now, however, Morsi has to contend with the fury of the judiciary.
The constitutional court called Sunday "the Egyptian judiciary's blackest day on record."
It described the scene outside the Nile-side court complex, where thousands of Islamist demonstrators gathered since the early morning hours carrying banners denouncing the tribunal and some of its judges.
A statement by the court, which swore Morsi into office on June 30, said its judges approached the complex but turned back when they saw the protesters blocking entrances and climbing over its fences. They feared for their safety, it added.
"The judges of the Supreme Constitutional Court were left with no choice but to announce to the glorious people of Egypt that they cannot carry out their sacred mission in this charged atmosphere," said the statement, which was carried by state news agency MENA.
