About 15,000 protesters have converged on the Greek capital's main square outside Parliament in the run-up to a vote by MPs on the 2013 budget which would once more cut pensions and salaries so Greece can qualify for its next vital batch of rescue loans.
MPs are expected to approve the legislation four days after a separate bill of deep spending cuts and tax increases for 2013-14 squeaked past with a narrow majority in the 300-member Parliament following deep disagreements among the members of Greece's three-party coalition government.
Approval of the austerity bill and the budget are key steps toward persuading Greece's international creditors - the International Monetary Fund and fellow eurozone countries - to release the next 31.5 billion euro (£25 billion) instalment of its bailout loans.
Without it, Prime Minister Antonis Samaras has said Greece will run out of euros on Friday.
But German Finance Minister Wolfgang Schaeuble, whose country is the largest single contributor to Greece's bailout, said in a German newspaper interview that international creditors will not be rushed when it comes to approving the loan disbursement.
"We all want to help Greece, but we won't be put under pressure," Mr Schaeuble told weekly newspaper Welt am Sonntag.
Mr Schaeuble said the so-called troika of debt inspectors is unlikely to deliver its report on Greece's reform programme by Monday.
He said Germany's parliament must have the chance to "check, discuss and decide" on the release of the funds.