Thousands of Spanish firemen, nurses and teachers protested noisily in Madrid Tuesday against crisis spending cuts that they say threaten crucial services in the region.

About 10,000 protestors filled the streets of central Madrid, 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 ($1,325) a month.

They also warned that the spending cuts -- part of nationwide measures that the new conservative Spanish government says will strengthen the country's 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.

"There are more pupils in each class and fewer teachers," said Barbara Tapiador, 33, a supply teacher. "This year there will be probably be no more work for me."

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 said retiring workers are not being replaced and substitutes are not being hired to cover for regular workers when they are on holiday.

"They have cut salaries and raised working time. Employment rights have been cut. The whole social protection system is in danger -- in education, in health," said Javier Figueroa, 43, a worker in a regional ministry and UGT representative.

"If they mistreat public workers, it is the whole of social welfare that suffers."

Spain's unemployment rate is already close to 23 percent and economists warn it is entering a second recession, following one in 2009 and 2010 brought on by the collapse of a construction boom and a global economic crisis.

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

Among the marchers were scores of Madrid firemen in their shiny helmets and black overalls, who set off firecrackers and drove around a miniature wooden fire engine, sounding its siren.

It was the latest in a series of demonstrations by public employees in Spain who say they are the first to feel the pain of cuts that the government says are needed to relaunch the economy.