A controversial government privatisation drive has sparked more tension in Greece with unions gearing up Wednesday for another general strike and online protesters planning Spanish-style square sit-ins.

The country's two main private and public-sector unions, GSEE and ADEDY, have already announced a 4 June protest in Athens ahead of a general shut-down and workers at three state entities targeted for sale have mobilised.

Staff at the Piraeus port authority (OLP) staged a harbour protest early on Wednesday, employees at Hellenic Postbank occupied their company offices for a second day and syndicalists at the Public Power Corporation (PPC-DEI) prepared to demonstrate in Athens later in the day.

Also Wednesday, a budding online movement styled after the Internet-driven "indignation" protests in Spain has called for peaceful gatherings at main squares in several Greek cities.

The turnout remains to be seen but the relevant event pages on Facebook have drawn thousands of signatories.

The Socialist government, already hit with two general strikes this year over its austerity measures, has struggled to convince its political opponents that there is no other way out of the country's economic impasse.

The Greek debt has exploded to over 350 billion euros (US$495 billion) and the recovery effort supervised by the European Union, the International Monetary Fund and the European Central Bank is running out of steam.

The Socialist government this week announced an "immediate" sale of lucrative state assets including OTE, the Balkans' largest telecoms operator, and the ports of Piraeus and Thessaloniki which rank among the busiest in the Mediterranean in terms of tourism and trade.

A new tax crackdown was also announced.

The conservative mayor of Piraeus, Vassilis Michaloliakos, on Wednesday pledged to resist the port's sale.

"There is no way that the port will be sold," Michaloliakos told To Vima radio, accusing the government of a "fascist-style mentality" for not bothering to consult with local officials.

Greece's eurozone peers have made the privatisation programme a condition of more assistance down the line.

"Greece has to take new commitments. Greece has to enlarge the ambition of its privatisation programme," leading eurozone policy-maker Jean-Claude Juncker said on Tuesday.

Last year Greece appealed to the EU, International Monetary Fund and European Central Bank for a 110-billion-euro loan to save it from looming bankruptcy, a first for a eurozone country.

A quarterly audit of Greek finances by the three creditors is heading into an unprecedented third week and has yet to approve the release of a fifth loan instalment worth 12 billion euros.

Greece will "most likely" go bankrupt without this money, Prime Minister George Papandreou admitted in a Sunday interview.
Athens is now trying to persuade the "troika" currently keeping Greece afloat -- the EU, IMF and ECB -- to maintain their funding.

"If the assessment of the so-called troika is positive then we can move to further steps, but it is too early to tell you what kind of next steps can be taken," Juncker said on Tuesday.

The head of the eurozone's council of finance ministers added that he is "strongly against a full restructuring" of Greece's debt but would consider "reprofiling," essentially giving Greece more time to repay, if Athens satisfies "all the conditions" laid out by its creditors.