The Spanish government is due to pass its 2013 budget, which is expected to include 39 billion euros ($50 billion) worth of spending cuts and tax increases.
The measures will come amid growing protests and expectations that Spain will seek financial aid from its partners in the 17-nation eurozone.
Spain, whose rising borrowing costs are seen as a threat to the stability of the eurozone, has come under increasing pressure to seek a bailout from the European Central Bank.
But a bailout will mean further austerity for the country already hit by recession and a 25 percent unemployment.
Thousands of protesters rallied near the parliament in Madrid for a second night on September 26 to protest against further austerity measures.
On September 25, riot police fired rubber bullets to disperse protesters.
Based on reporting by AP, AFP, and the BBC