Greece's Socialist prime minister, George Papandreou, offered to step down Wednesday in return for the creation of a unity government with the opposition New Democracy party, dpa quoted government sources as saying. The move was designed to persuade parliament to approve 28 billion euros (41 billion dollars) worth of spending cuts and tax hikes by 2015. Sources said the prime minister would be willing to stand down and agree to a commonly-accepted new head of government with the conservative opposition. The development came as thousands of Greeks took part in a 24-hour strike over a wave of austerity measures. Protesters in Athens pelted stones at police, who retaliated by firing tear gas and stun grenades, as tens of thousands of people marched towards parliament. Heavy clouds of tear gas filled the air around the capital's main Syntagma Square, where more than 30,000 people had gathered. Nearly a dozen people were injured, including a police officer, while more than 30 people were detained. Thousands more took part in a general strike that crippled transport and public services. The government's austerity measures are needed to secure continued funding from a 110-billion-euro international bailout package needed to stave off bankruptcy. The mid-term fiscal plan is to include an increase in taxes on real estate, soft drinks and restaurant bills. It will also cut the public sector workforce by a fifth, from the current 750,000. The government, which faces resistance from both the opposition and members of its supporting Socialist party, is also hoping to introduce a four-year privatisation programme worth 50 billion euros. A member of parliament from Greece's ruling Socialists resigned his cabinet seat Tuesday, leaving the party with a slim majority of 155 out of 300 ahead of a crucial vote later this month. Another said he would vote against the bill, making what had once seemed a done deal less certain. If the bill is not passed, the southern Mediterranean country will be cut off from its rescue funding and will default on its debt, likely setting off a financial chain reaction within Europe. In a sign of tension in the capital, activists marched in anger towards parliament in Syntagma Square in an effort to stop parliamentarians from debating the bill, yelling "Thieves, Thieves - give us back our money." Many protesters demanded that the government hold a referendum on the austerity measures. "This is something that will affect us for years to come so the democratically just thing to do is to call for a referendum," said Michalis Lagoumtzis. Police fired tear gas into crowds as demonstrators threw molotov cocktails and ripped up marble stones from stairs and sidewalks to throw at riot police and towards limousines carrying several officials, including the prime minister. Prime Minister George Papandreou had previously appealed for national consensus on the mid-term fiscal plan, which both the European Union and the International Monetary Fund have said is necessary for the release of 12 billion euros in aid next month. Athens needs the money to pay off maturing debt. "We will continue to make the decisions necessary to take the country out of the crisis," Papandreou had said at the start of an emergency meeting with President Carolos Papoulias. Meanwhile, government offices and banks remained shut and ferries were anchored at ports across Greece. The walkout also halted train services, closed schools and public services and left hospitals operating with emergency staff only. Greek journalists also walked off job for several hours, leading to a news blackout. Flights, however, were operating smoothly after the air traffic controllers' union called off their participation in the strike.