Greek sailors, customs officials and other government employees went on strike on Monday and magistrates were to follow suit to protest cutbacks ahead of nationwide strikes this week.
No vessels entered or left the main Greek port of Piraeus after 6:00 am (0300 GMT), the mercantile marine ministry said following the 48-hour strike call that the National Sailors' Union (PNO) hailed as a "total success."
The PNO flayed the "barbaric offensive targeting social gains," in Greece, which experts say needs to cut its debt load, equal to more than a year and a half of its economic output, by roughly half to put it back on a stable financial footing.
Greece's two main unions are staging a two-day general strike on Wednesday and Thursday to denounce the new government austerity cuts intended to resolved a debt crisis that has shaken the eurozone.
The strike is timed to coincide with a vote in parliament on the new batch of belt-tightening measures as part of reforms mandated by the EU, the IMF and the European Central Bank, which last year earmarked a 110 billion euro ($151 billion) loan for Athens.
Later on Monday, court officials and magistrates will halt work at noon, three hours before the time originally scheduled, and some have threatened to occupy the courts.
Finance and customs officials and government employees also stopped work while the public media, including Net television and the national news agency Ana, did not function for a fifth day.
Greece has a sovereign debt of over 350 billion euros ($480 billion) and faces interest repayments of 17.9 billion euros in 2012, up from 16.3 billion euros in 2011.
Rubbish collectors in Athens have been on strike since October 2. The government brought in private contractors to clean up the garbage over the weekend and has threatened to leave strikers without pay.
The controversial austerity measures include layoffs and placing about 30,000 public sector workers on furlough which they say are driving salaries to sub-poverty levels.