Around 100,000 workers have taken industrial action this year over demands for minimum wage to be rolled out nationwide

The Egyptian army temporarily took over parts of Cairo's bus system this week, after strikes stopped services in most of the capital's 28 municipal garages amid ongoing industrial action in which a reported 100,000 workers have downed tools this year.

The surge in worker activism was one of the main reasons for the mass resignation of Egypt's interim cabinet on Monday. Strikers' demands differ from sector to sector, but the most common is a plea for the new minimum wage – awarded to around a third of state employees in January – to be rolled out to all public- and private-sector workers.

The labour movement was a leading force behind the 2011 uprising that ousted President Hosni Mubarak, while strikes also helped to destabilise the rule of Mohamed Morsi during the final months of his presidency.

Now, several months after his overthrow, workers had finally given up hope of his successors doing any better, said Hoda Kamel, a senior official with the Egyptian Federation for Independent Trade Unions (Efitu), a group founded during the 2011 uprising.

"For the past six months, the people waited for the government to be the government of the revolution – as they had promised," Kamel said. "But when January came, people realised it was a trick because the minimum wage is just for a very small part of people working in the government, not for the private-sector or most government workers."

Doctors have also called for an increase in salaries and the health budget. Labour leaders said 87% of state doctors joined strikes on Wednesday, though ministry spokesmen said only 23% took part.

Officials said Egypt could not afford to pay people more.

"Making demands that exceed logic will destroy the country," the new prime minister, Ibrahim Mahlab, said during his first speech in office this week.

But the labour movement is furious that decade-old demands which contributed to the overthrow of two presidents had still not been met. Even those allocated the new wage are themselves frustrated because the sum – 1,200 Egyptian pounds (£120) a month – is a figure that workers first demanded in 2008, and it has not been updated to reflect huge increases in commodities prices.

Kamel said: "Six years later it's not enough at all to pay for food, for rent, for medical treatment, for clothes. Now we need 2,000 at the minimum – and even in a year that will not be enough."

Bus drivers reached an agreement with the government on Thursday afternoon, and the current wave of strikes is still smaller than an earlier series in 2012.

But leaders warned that wider labour action would clearly worsen in the months ahead, destabilising whoever is elected to succeed Morsi as president this spring.

Tarek Elbehiry, vice-president of the bus drivers' syndicate, said: "We thank the armed forces for their efforts to solve the citizens' problems, but who is going to solve ours? Who is going to meet our legitimate demands? I'm disappointed indeed, and I'm afraid of a third revolution that will be carried out by the workers."

• Additional reporting by Manu Abdo