Deposed Egyptian president Mohamed Morsi's supporters will boycott a referendum on a new constitution next month.
The supporters are also planning to organise a campaign against the vote, a spokesman said.
According to the Express Tribune, the Anti-Coup Alliance led by Muslim Brotherhood movement had initially considered calling on its supporters to vote against the constitution.
An extensive police crackdown however on the supporters has decimated their grassroots network, weakening their chances of defeating the new constitution at polls.
Hamza al-Farawy, a spokesman for the Anti-Coup Alliance, which demands Morsi's reinstatement, said that the group rejected any vote under military rule.
According to the report, the referendum on January 14 and 15 is expected to ratify the new constitution, which replaces the one suspended by the military when it ousted Morsi in July.
.