The trade union representative on the constitution panel has resigned over the removal of the 50 percent quota of parliamentary seats for workers and farmers.
Abdel-Fattah Ibrahim, head of the state-controlled Egyptian Trade Union Federation, described the move as a "massacre of Egypt's workers and farmers."
"This will marginalise Egyptian workers," Ibrahim told reporters on Tuesday.
"I call all classes of Egyptian workers to vote against this constitution," Abdel-Fattah Ibrahim added.
"We demand the rights of the workers who stood with the January revolution. We demand the constitution committee and the government reconsider their position on the reservation of seats in parliament for workers and farmers," he said.
The panel's official spokesperson Mohamed Salmamawy disputed Ibrahim's claims and said representatives of workers and farmers had agreed to the move.