The amendments to the country's labour union law was ratified amid the political crisis that ensued after Mursi issued a Constitutional declaration immunising his decisions from judicial appeal and granting him absolute powers.
This is the first law to be decreed by Mursi following his 22 November declaration, which granted his decisions immunity against challenges.
According to the new law, the manpower minister, who is affiliated with the Muslim Brotherhood, may appoint workers who are members of the group in leadership positions that would become vacant in the Egyptian Trade Union Federation (ETUF), which has always been affiliated with the government.
The new law cancelled Article 23, which allowed union membership without age limit.
It also grants the minister the right to appoint board members of unions if the minimum required number of members is not attained for any reason, to fill the vacant seats on the board.
Labour activists fear the law paves the way for Brotherhood control of the federation.
Ahmed Abdel Zaher, chairman of the ETUF, criticised amendments to the law.
The amendments, he said, violate international agreements Egypt had signed with the International Labour Organisation, especially those related to trade unions' freedom from governmental interventions.
Zaher said amendments to the law could prompt the ILO to blacklist Egypt as one of the states breaching trade union freedoms and allowing government intervention in labor affairs.
Kamal Abu Eita, head of the Egyptian Federation of Independent Trade Unions, said federation members would attend tomorrow's demonstrations to protest the new labour law, adding that they plan to confront the amendments with partial and all-out strikes.
He added that Mursi