Several thousand anti-austerity protesters in Spain have marched down a major road in Madrid banging pots and pans.

Many protesters also blew whistles as they blocked part of the Castellana boulevard carrying placards saying "We don't owe, we won't pay".

With unemployment nearing 25%, Spain has introduced biting austerity measures as well as financial and labour reforms in a desperate bid to lower its deficit and assuage investors' misgivings.

Spain has been granted a 100 billion euro loan by the Eurozone group of nations to help its banks worst hit by the collapse of a bloated real estate sector.

Still, Spain's economy is in a double-dip recession with a forecast to shrink by 1.5% this year and by up to 0. 6% in 2013.