The strike will take place Tuesday and Wednesday, the General Confederation of Workers of Greece (GSEE) said. A rally is planned for Tuesday that will end outside the Parliament building.
Greece's Parliament is due to vote Tuesday on a tough five-year package of tax increases and spending cuts.
The austerity measures must be passed if Greece is to win the last $17 billion tranche of a $156 billion bailout package from other European nations that was granted in 2010, and also to clear the way for another potential bailout package to keep Greece afloat going forward.
The unions' call for strike action comes less than two days after Prime Minister George Papandreou and his reshuffled Cabinet survived a vote of confidence, amid widespread public opposition to further austerity moves.
The economic crisis has inspired rioting in the streets of Athens in recent weeks, where protesters have thrown firebombs and clashed with armored police. (read more)