Hundreds of Spaniards defied a ban on their makeshift protest camp in the heart of Madrid for a fourth straight day Thursday, denouncing the country's two main political parties as selfish and useless in dealing with the country's economic crisis.

After spending the night in Puerta del Sol plaza, they shook water from plastic sheeting used to shelter from the rain, held small assemblies with bullhorns, handed out donated, free food such as fruit and sweet rolls, and prepared for another rally in the evening.

Similar demonstrations in other Spanish cities are adding anger to what has been a humdrum campaign for local and municipal elections this weekend.

Spain is only now slowly recovering from nearly two years of recession. Its jobless rate has soared to a euro zone high of 21.3 per cent. Prospects for significant economic growth soon are slim.

Miguel Arrastia, 26, said protesters are angry that spending cuts and other austerity measures imposed to deal with Spain's deficit and other problems are making people suffer even more. He is an unemployed surveyor.

"This protest is a spontaneous thing, and I think it is happening at the right time because it is right before the elections and we are showing that no party is capable of dealing with this crisis," he said.

Arrastia said that recent pro-democracy uprisings in North Africa and the Middle East served as an inspiration — a reminder of what people working together can achieve.

"They were an influence because they gave us strength. Those people were able to stand up to dictators, so why cannot we" take on a stagnant political system at home, Arrastia said.

Inspired by Arab protests

The demonstrators in Spain have a range of complaints but are united behind the slogan of "Genuine Democracy Now." Ramon Cotarelo, a political science professor at Complutense University in Madrid, said the protests, which began over the weekend, are the culmination of a mix of woes and other factors.

He cited the economic crisis, contagion from the Arab countries, rapid-fire communications over the Internet, people being fed up with ineffective and sometimes corrupt politicians, and elections in which some candidates are in fact under formal investigation for corruption.

"Suddenly there is a spark and everything explodes," Cotarelo said. Crowds that have packed Puerta del Sol this week have pledged to stay there until after the elections this weekend.

The Madrid electoral board banned the demonstration in the square Wednesday, saying it could influence the elections Sunday. But the ruling appeared to have the opposite effect and — spurred on by social media messages — thousands of people of all ages swarmed into the square, packing it by midnight.

The national electoral board is to decide later Thursday whether the demonstrations are legal in the run-up to voting day. The demonstrations, initially organized by students and unemployed and disaffected youths, are a spillover from countrywide demonstrations Sunday.

They have triggered a lively debate throughout the country on how the crisis has been handled by the politicians and financial institutions.

The governing Socialist party of Prime Minister Jose Luis Rodriguez Zapatero is tipped to suffer a resounding defeat in the elections. In turn, the leading conservative opposition Popular Party is expected to make huge gains.

General elections are not scheduled until 2012.

With files from The Associated Press