Greece's public transport networks ground to a halt Friday after trade unions called for a 48-hour strike to protest controversial government plans to overhaul pensions and increase taxes, as demanded by international creditors.

No public transport service in Athens was working Friday morning as metro, tram, bus and rail workers began a strike that is set to run through Sunday, unions said.

The only mode of transport still available in the capital was taxis.

The announcement on Thursday of a general strike came after Greece's parliament said the government's pension and taxation reform bills would be debated and voted on this weekend.

Train services across the country were halted, and ferries linking mainland Greece to the islands remained anchored in port.

The powerful PNO seafarers union's strike, which also began Friday, is set to last until Tuesday morning.

Intercity coach services and air travel were not affected by the strike.

Other public services were also affected.

The journalists' union joined the strike, and on Friday most public and private radio and television channels did not broadcast news bulletins.

Changes to Greece's pensions system were demanded by creditors as a condition of the country's third bailout in five years, worth 86 billion euros ($95 billion), agreed in July last year.

The strike comes ahead of a meeting of eurozone finance ministers to discuss Greece's bailout on Monday in Brussels.

The meeting was initially scheduled for Thursday but was cancelled amid disagreements between Athens and the International Monetary Fund, which has demanded more reforms from Greece.

Marches are expected in Athens and other cities this weekend, coinciding with celebrations for International Workers' Day this Sunday which were postponed from May 1 owing to the timing of Orthodox Easter.

The strikes are the fourth to be called since Prime Minister Alexis Tsipras's leftist government won re-election after organising a referendum on the country's bailout.