Workers from the Nasr Automotive, Ideal and Steam Boilers factories on Tuesday staged protests outside the presidential palace in Cairo, demanding early pensions and profit shares.
An official tried to persuade them to bring the protest to the minister of manpower as opposed to the president, but the workers refused to leave.
Three protesters fainted from the heat.
The Steam Boilers factory stopped operations following a ruling in September to invalidate its privatization contract and return its ownership to the state.
Nasr Automotive has also closed down five factories, which the workers demand be re-opened.
