Egypt's administrative court has suspended the presidential decree, state-run MENA news agency reported.
The court said it acted because the upper house of parliament had not returned the amended electoral law to the Constitutional Court for review.
The court ordered that the elections law be referred to the Supreme Constitutional Court.
Last month, Mursi had called for House of Representatives elections to start on April 22 and conclude in late June.
The main opposition coalition National Salvation Front had said that it would boycott the vote, saying that there were no guarantees that the elections would be free and fair.
According to the new Constitution, the Supreme Constitutional Court is supposed to rule on the election law, but the Shura Council's Constitutional and Legislative Affairs Committee head Abdel Mohsen has argued that the SCC cannot review laws after they are passed by the council.