Mohamed Abdel Aziz, Tamarod's political communications officer, has urged interim President Adli Mansour not to approve the new law on demonstrating in Egypt.
Tamarod is a youth movement that organized demonstrations last year to topple former President Mohamed Mursi.
On his Facebook page, Abdel Aziz called for referring the law to the National Council for Human Rights to rewrite it in a manner that preserves the right to peacefully demonstrate.
The new protest law, approved by Prime Minister Hazem al-Beblawi, grants the Interior Ministry the right to break up demonstrations by force following some formalities and completely prohibits the right to stage sit-ins.
Abdel Aziz, a member of the 50-strong committee in charge of amending the constitution, previously slammed the protest law, describing it as "unjust".
Taking action against non-peaceful demonstration should be done by law and should not be used to restrict or stop peaceful demonstration, he added.