The strikes began Wednesday after weeks of anti-government protests calling for less corruption and more democracy in the country's troubled government.
Demonstrators have been crowding Cairo's Tahrir Square, calling for President Hosni Mubarak to resign. Wednesday, activists also gathered at parliament, the Cabinet and the Health Ministry buildings, all a few blocks from the square.
Protesters were urging labor strikes despite a warning by Vice President Omar Suleiman that calls for civil disobedience are "very dangerous for society and we can't put up with this at all."
Strikes erupted among railway and bus workers, state electricity staff and service technicians at the Suez Canal, in factories manufacturing textiles, steel and beverages and at least one hospital.
Suleiman issued what appeared to be an ultimatum. He said that protesters have two options: dialogue or coup.
If dialogue is not successful, he said, the alternative is "that a coup happens, which would mean uncalculated and hasty steps, including lots of irrationalities." The comment appeared to be a possible hint at imposing military law - which would be a dramatic escalation.
Opposition leaders said the ultimatum amounts to a threat.
Suleiman is also rejecting any immediate departure of Mubarak, who is still appearing in photo ops.
At the White House, the Obama Administration said it is not backing off its pressure on Mubarak or its support of the protesters in Cairo.
Meantime, Egypt's most famous tourist attraction, the Pyramids of Giza, reopened to tourists on Wednesday. Tens of thousands of foreigners have fled Egypt amid the chaos, raising concerns about the economic impact of the protests.
The Associated Press contributed to this report.