Portugal's biggest union CGTP on Thursday called for a general strike on March 22 to protest against the centre-right government's labour market reforms.
"We call for a general strike ... against exploitation and impoverishment," CGTP secretary general Armenio Carlos said following a meeting of national union leaders.
"This is a general strike about the rights of workers and the young generations," Carlos said.
Two previous general strikes held since the beginning of the debt crisis were organised by both the CGTP, close to the Communist Party, and the UGTP, a historically more moderate labour union.
But the two unions have since feuded over controversial reforms pushed through by Portugal's conservative government.
The labour reforms, which were sanctioned by the UGTP but rejected outright by the CGTP, increase hiring and firing flexibility and abolish several holidays and vacation days.
UGT Secretary General Joao Proenca said his union would not participate in the March strike as it was a "protest movement without defined objectives".
He said the agreed reforms marked an "important step and we must maintain this path and not choose conflict for conflict's sake".
Government spokesman and Parliamentary Affairs Minister Miguel Relvas said that while the right to strike must be respected, the government was "seeking the conditions for Portugal to overcome the current situation".
The controversial reforms are part of a plan to meet the conditions set by the European Union and International Monetary Fund for their bailout of debt-stricken Portugal in exchange for a loan of 78 billion euros ($103 billion).
Austerity has hurt the economy with unemployment hitting a new high of 14 percent in the final quarter of last year.
And the Portuguese economy contracted by 1.5 percent in 2011, provisional data from the INE statistics institute showed on Tuesday.
The strike call comes as officials from the so-called 'troika' of the European Union, European Central Bank and the International Monetary Fund continue a two-week review of the economy, checking Portugal's progress since last year's bailout.
Lisbon received the bailout in return for a series of tough austerity measures to slash public spending and increase revenues.