More than 20,000 public sector workers demonstrated in Athens Wednesday in a strike against deeper austerity cuts that shut down courts, schools and transport, including air traffic. Police used tear gas to clear some of the protesters, who included a 500-strong anarchist group, from central Syntagma Square opposite parliament, an AFP reporter said. The protests organised by the two main Greek unions, ADEDY and GSEE, came ahead of a general strike on October 19, which will also affect banks and shops. It was called in response to new taxes, wage cuts and layoffs imposed by a government, fighting to avert a default on its debt payments, as the next tranche of an international aid hangs in the balance. \"Every time the public deficit gets bigger they impose new taxes, life is just getting too expensive,\" said Stavros and Helena, a married couple employed at the city of Athens. \"They should just put us on a boat and send us away,\" they told AFP. \"All workers must unite and coordinate their forces against this storm of measures that strike income and labour rights,\" ADEDY chairman Costas Tsikrikas told Flash Radio. \"If we don\'t resist we will lose everything,\" he said. Civil servants are protesting a plan to put some 30,000 employees on labour reserve or furlough, during which they will be on reduced pay for a year as they try to find other jobs.  The workers concerned already suffered sweeping wage cuts last year. \"Labour reserve equals layoffs,\" read a banner carried by municipal workers. Communist unions urged Greek to \"organised resistance\" as they marched on parliament. The 24-hour walkout has shut down ministries, town halls, museums, schools and courtrooms, as well as flights in Greece. It also brought trains to a halt and hospitals were reduced to emergency staffing. The labour plan, accompanied by downsizing at scores of state entities, is designed to ease the state payroll as the government struggles to balance its bulging public deficit. But there has been mounting criticism even within the ruling Socialist party. \"We have fallen behind in three crucial reform fields -- civil service wages, tax evasion and privatisations,\" former labour minister Louka Katseli told private television station Mega. \"We gave our (EU) peers an excuse to say that necessary reforms were not carried out in the summer,\" she said. The additional austerity cuts are mandated by Greece\'s international creditors -- the EU, IMF and European Central Bank -- under an economic recovery programme launched last year in return for a 110-billion-euro ($149-billion) loan. Greece\'s state reserves to pay wages and pensions run out in November. A high-level mission from the three organisations, commonly called the \'troika\' in Greece, is currently conducting an audit of Greek finances. That will determine whether or not they release of an eight-billion-euro loan tranche next month. The auditors caused widespread shock this week with a demand that the government revise collective labour agreements in the private sector. \"Wages in Greece are low compared to other countries but there are other company costs that are high such as social insurance contributions,\" Katseli said. The country is trapped in a deepening recession and many Greeks point out that the cumulative cuts are only digging a deeper hole for the economy, which is expected to contract by 5.5 percent of output this year. As the recession has repeatedly neutralised part of the sacrifices, there is concern that additional cutbacks to meet slipping fiscal targets are inevitable. The Greek finance minister on Tuesday argued that no new austerity measures were needed. To meet its targets, the government last month announced a new property tax and slashed income tax breaks by over a half. On Tuesday, global financial markets were in turmoil once again on concerns that Greece might finally default. Investors worried that the banks, especially in Europe, were under increasing pressure from their exposure to Greek government debt. The Athens stock exchange plunged to an 18-year low after EU officials postponed a bailout of debt-wracked Greece.