Nour Party chairman Younes Makhion has called for the controversial protest law to be scrapped and for the release of non-violent detainees.
The Salafist leader said the penal code was sufficient to deal with violent protesters until a new law is passed by the upcoming parliament.
Makhion, who has frequently called for an end to protests by loyalists of deposed president Mohamed Morsi, has been critical of the protest law since it was issued by interim president Adly Mansour in November.
Makhion, whose party backed Abdel-Fattah El-Sisi in the May presidential election, has defended his anti-protest stance since last December by saying the country can only move towards democracy through elections, not protests.
However, days after the protest law was issued the ultra-conservative party warned that the law “provides a legal basis for suppression,” ignores the demands of civil society and political groups, and contradicts international standards.
"I demand an immediate decision and the release of detainees who have not been involved in violence.
"I think such steps will have a huge impact on reducing the intensity of divisions among Egyptians," said Makhion on Tuesday, adding that it would further encourage "national alignment behind the new leadership."
The controversial law, which was issued months after the interim authorities launched a crackdown on Islamists, has led to the arrest of thousands on charges of protesting without police authorisation.
Supporters of law have claimed it is necessary to allow the police to ensure that demonstrations are peaceful and that stability returns after years of turmoil.
A court will look on Tuesday into a lawsuit – filed by the Egyptian Centre for Economic and Social Rights – challenging the constitutionality of the anti-protest law.
Several non-Islamist political forces have announced they will attend the court session.