Madrid's central Puerta del Sol square filled for the first time since the "indignant" protesters camped there last May, as people gathered to protest against reforms introduced by prime minister Mariano Rajoy's government.

Protesters also marched through Valencia, capital of a heavily indebted and corruption-plagued region run by Rajoy's People's party, and Barcelona. Unions claimed more than half a million people demonstrated across the country.

The protests came two weeks after Rajoy, who became prime minister in December, introduced a labor decree making it easier for employers to fire workers and opening the door to wage cuts.

Rajoy's reforms are part of a program designed to create jobs. Spain has the developed world's highest unemployment rate. But with the economy set to shrink this year by 1.7%, even the government admits the shocking 23% unemployment rate will rise in the short term.