More than 100,000 people packed the Portugese capital on Saturday in the largest rally against austerity and economic hardships since the country resorted to accepting a bailout last May.
The mass rally in Lisbon's Palace Square occurred just days before international lenders were due to start the quarterly evaluation of the bailout implementation from the European Union and International Monetary Fund on Wednesday, Reuters reports.
It comes amid concerns that Portugal may need more bailout funds, if not a debt restructuring like Greece.
The peaceful rally under the banners of the country's largest union CGTP, which in January refused to sign a pact with the government on labour market reform, showed social strife is running strong.
Spending cuts and tax increases needed to meet the fiscal terms of the bailout have caused the worst recession in Portugal since the few turbulent years that followed the 1974 return to democracy.
Unemployment is at a record of about 13%.
However, Portugal's debt crisis has so far failed to provoke the scale of labour protests seen in Greece.
There have been two general strikes in the past two years and workers in transport and other sectors have staged regular stoppages.