Many Greeks are opposed to further cuts, which the government says are absolutely crucial Eurozone finance ministers have postponed a final decision on a 12bn-euro (£10-bn) loan to Greece until it introduces further austerity measures. They said they expected to pay the latest tranche of a 110bn-euro EU and IMF aid package by mid-July.
But it would depend on Greece passing 28bn euros of new spending cuts and economic reforms, they added.
Earlier, thousands of people gathered outside the parliament building in Athens to oppose any further cuts.
Waving banners and Greek flags, they shouted: "Thieves! Traitors!"
Prime Minister George Papandreou meanwhile told MPs that they had to support the austerity measures demanded by the European Union and International Monetary Fund to avoid a "catastrophic" default.
They will vote on Tuesday on a confidence motion in Mr Papandreou's cabinet, which he reshuffled last week amid public unrest.