Thousands of firemen, nurses and other public sector workers protested noisily in Madrid Tuesday against crisis spending cuts which they say threaten crucial services in and around the Spanish capital.

Several thousand protestors filled an avenue in the centre of the city, sounding horns and drums, waving flags and yelling "Public services are not for sale!"

They were protesting the conservative regional government's decision to extend their working hours and cut sickness benefits for public sector workers, some of whom earn little more than 1,000 euros a month (1,300 dollars).

They also warned that the spending cuts -- part of nationwide efforts under a new conservative Spanish government to strengthen public finances -- were undermining social care and emergency services.

"The hospitals are running at half capacity because there are not enough staff," said Dolores Escrivano, 57, a nursing auxiliary, who demonstrated wearing the blue vest of her CSIT union.

"There are hospital beds lying empty because there are no staff," she said, referring to the regional administration.

The UGT, one of the major unions that organised the protest, says thousands of jobs are under threat across the public sector in Madrid.

Protestors complained that retiring workers are not being replaced and replacements are not being hired to cover for regular workers when they are on holiday, resulting in poorer service in social services, schools and hospitals.

Among the marchers were scores of Madrid firemen in their shiny helmets and black overalls.

"There is no budget to buy tools to repair our vehicles," said one, Javier S., who asked that his full name not be given.

"There are fire stations with vehicles that have lots of faults. It affects our safety and that of the citizens."

The protest march massed in an avenue near Madrid's Prado museum before setting off for the Puerta del Sol, the central square that has been a focal point for a wave of social protests since May last year.

Spain emerged only at the start of 2010 from an 18-month recession triggered by a global financial crisis and a property bubble collapse that destroyed millions of jobs and left behind huge bad loans and debts.

The country's jobless total hit 5.27 million people at the end of 2011, pushing the unemployment rate to 22.85 percent, the highest level among members of the Organisation for Economic Cooperation and Development.