Greek trade unions warned on October 21 of further strikes in the next week after parliament approved new harsh cutbacks amid mass protests that left one man dead and about 200 injured.
Civil servants' union Adedy secretary-general Ilias Iliopoulos said the new law "will not be implemented" and accused the government of ignoring popular dissent.
Greece's main private-sector union, GSEE, was also planning new strikes.
GSEE board member Stathis Anestis said: "We plan long-running opposition to ensure that the crippling cutbacks imposed by our loan shark predators are not enforced."
More than 150,000 people took to the streets of Athens on October 19 and 20 during a two-day general strike against the cutbacks.
The new measures include more pension and state salary cuts, civil service staff cuts and a cut in the tax-free threshold.
Greek ferry workers, municipal workers and nurses were still on strike on October 21.
A 53-year-old construction worker died of heart failure after attending the October 21 mass rally, and 74 protesters and 32 police officers were hospitalised with injuries.
The austerity measures were passed in parliament by 154 votes to 144 in the 300-member parliament.
Greece now heads into a series of negotiations in Brussels, but fury at the government echoed across Athens.
Pensioner Kleanthis Kizilis said at the protest: "That it was voted on is one thing. Its implementation is another. The people will tear it apart, they will dismiss it in practice."
[Abridged from Morning Star.]