Hundreds of thousands of demonstrators rallied in Madrid, Spain on Sunday in defense of the region's primary care services, warning that plans to overhaul the system would "destroy" local health care. 

Huge crowds rallied at four points across the capital and marched on city hall in a mass protest under the slogan, "Madrid rallies in support of public health care and against the plan to destroy primary care services." 

Primary care services in the Madrid area have been under huge pressure for years due to a lack of resources and staff, with the situation worsened by poor regional management, unions say. 

A regional government spokesperson said there were 200,000 people out on the streets, but organizers gave a figure three times higher, saying 650,000 demonstrators had joined the protest. 

Aerial shots over the main boulevards leading to City Hall showed a vast sea of protesters surging in from all directions, among them many doctors and health care professionals, union members and politicians. 

"Your health should never depend on your wallet," read one huge green banner, while others read, "Health care is not for sale, it must be defended" as thousands of voices demanded the resignation of the region's right-wing leader Isabel Diaz Ayuso.

The protest, called by local associations and municipalities, took aim at the health policies of Ayuso's regional government, its push for public-private health care partnerships and its restructuring of the primary care system. 

One doctor working at an emergency unit in the region told reporters the cutbacks, staff shortages and mismanagement of the health services were putting an impossible strain on medical staff. 

"I haven't slept properly for six weeks. I'm barely surviving. I keep having anxiety attacks which I can only control with breathing exercises or sometimes medication. And all my colleagues are the same," said Isabel de Barrio, 59.

The protest comes ahead of a planned strike by nearly 5,000 regional family doctors and paediatricians scheduled to begin on November 21, due to "the overload of work, endless appointments and lack of time with patients."