Protesters clashed with police in Madrid on Tuesday night as the government were preparing a new round of austerity measures, Euronews reported.
Around 1,500 police officers in riot gear blocked access to the parliament building from the thousands who came together in the capital.
Protesters were charged by baton wielding officers and had rubber bullets fired at them. The tactics have been defended by the government and described as heavy-handed by the opposition socialists.
"The police's attempts to contain the protest went too far. The images released of the police charging were excessive and the differences when compared with the way these situations were dealt with when we were governing are clear to see," said Eduardo Madina, Secretary General of the Socialist Group in the Spanish parliament.
Interior Minister Jorge Fernández Díaz had a different opinion of the events. He said that "attempting to occupy the Congress or trying to cause problems for the members of parliament while a session was taking place could not be permitted because it is an attack on the constitution and the penal code". He believes that "the police acted correctly".
The protest had been organized by different activist groups on the internet over the recent cuts in public salaries and to health and education.
Prime Minister Mariano Rajoy is expected to announce new austerity measures for the 2013 budget on Thursday.