The growing wave of labour unrest has been unleashed by the democracy uprising that ousted President Hosni Mubarak.
The statement by the ruling military council that took power from Mubarak appeared to be a final warning to protest organisers in labour and professional unions before the army intervenes and imposes an outright ban on gatherings, strikes and sit-ins.
In Cairo's Giza district, hundreds of ambulance drivers demonstrated to demand better pay and permanent jobs.
They parked at least 70 ambulances on a roadside along the river, but did not block the main road. In downtown Cairo, hundreds of police demonstrated for a second day for better pay.
They also want to clear their reputation, further tarnished by the deadly clashes between protesters and security forces.
Some carried portraits of policemen killed in the clashes.
It said Egypt needed a quieter climate so the military can run the nation's affairs at this "critical stage" and eventually hand over the reins of power to an elected and civilian administration.
The statement also warned that strikes and protests hurt the country's security and economy and gave a chance to what it called "irresponsible parties" to commit "illegal acts." It did not elaborate.
Some small scuffles broke out as soldiers attempted to clear all the remaining demonstrators from Cairo's Tahrir Square on Monday, the giant traffic circle that was turned into a protest camp headquarters for the 18-day revolt.
The few dozen remaining protesters say they won't leave until all those detained during the revolt are released.
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.