The Greek authorities are bracing for a broader campaign of civil disobedience as a nation infuriated by austerity and incensed at the engagement of EU and IMF "monitors" takes matters into its own hands.

Sales of generators have shot up as households, resisting further belt-tightening, have sought to bypass a new property tax that the beleaguered government will collect through electricity bills.

Announcing the measure in a desperate attempt to plug a budget black hole, the finance ministry warned that failure to pay the tax would automatically result in power supplies being disconnected.

"But when 70% of Greek households don't pay it what are they going to do, cut off the whole lot?" asked Giorgos Zisimos, a shopowner-cum-driver.

Rather than dampen Greece's anti-tax revolt, last week's landmark decision at an EU summit to write off 50% of Greece's debt mountain while giving Athens another €130bn (£114bn) in rescue funds, appears only to have bolstered resistance. Many fear the deal will mean more austerity on top of wage, pension and benefit cuts already enforced by the socialist administration in exchange for the foreign aid it needs to stave off default.

Although hailed by the prime minister, George Papandreou, for providing "necessary breathing space", the accord has also been harshly criticised for ceding too much sovereignty to its international creditors. Outraged Greeks are asking how much say they will have in their own affairs after the EU made clear that monitors would be relocated to Athens to supervise the economy. On Friday, anger reached boiling point as anti-austerity protesters, some carrying "Merkel = Hitler" banners, others burning German flags, disrupted national parades commemorating Greece's entry into the second world war.

"Greeks are a proud people and the EU should bear this in mind," said Yiannis Dimaras, who was expelled from the ruling Pasok party in June for refusing to endorse painful cost-cutting measures demanded in return for a second aid package 14 months after Athens was first bailed out to the tune of €110bn. "The prospect of more measures will bring more social explosions. The civil disobedience that we are seeing is partly about protest but also about people just not having the money to pay such extras. How can someone who earns €500 a month suddenly be called on to pay a property tax? The government I think is going to have huge difficulty enforcing this."

Nothing has galvanised public opinion more than the unpopular property tax. The finance ministry says that as a result of rampant tax evasion it is owed €40bn in unpaid taxes. It hopes the levy, whose lifespan is as yet unspecified, will raise about €2bn by the end of the year.

The civil disobedience movement, which began with Greeks refusing to pay road tolls and has seen ministries and government buildings being taken over in a wave of strikes and protests, has grown to such an extent that even elected local officials have thrown their weight behind it.

With thousands of electricity bills yet to be printed, militant unionists at the public power corporation, DEH, who recently took over the company's printing press, have threatened to step up action. "We are not going to do the government's dirty work," railed Nikos Fotopoulos who heads the union. "Electricity is a social commodity, not a means to collect taxes. We will do everything to ensure that unemployed people, poor people do not have their electricity cut."