Public transport crawled to a standstill and flights were grounded in Portugal Thursday as workers staged their fourth general strike in two years against austerity measures adopted in return for a massive international bailout. \"This is an exceptional strike in terms of worker participation,\" said Armenio Carlos, the head of the country\'s biggest union, the Communist-led General Confederation of Portuguese Workers. Portugal\'s second-largest union, the General Union of Workers, which had worked with the government on a reform of the labour code, seconded the strike call, a sign of dwindling patience with spending cuts and tax increases. Its secretary general Carlos Silva said \"the goals of the strike have been reached\", claiming that five million people followed the stoppage, or half of the active population. The last time the two unions banded together in a general strike was in November 2011, just five months after Prime Minister Pedro Passos Coelho\'s centre-right coalition took office. The unions are angered over a fresh package of austerity measures unveiled in May that include raising the weekly work hours of state employees from 35 to 40 and slashing 30,000 out of 700,000 jobs in the bureaucracy. The government says the measures will reduce public spending by 4.7 billion euros ($6.1 billion) by 2015. Thousands of people marched through the historic centre of Lisbon to parliament, whose broad marble staircase was protected by a police cordon. \"Protests worked in Brazil. Portuguese people need to get out into the streets and express their anger. We have to continue,\" said David Santos, a young unemployed man who attended the Lisbon rally in a reference to the wave of protests sweeping Portugal\'s former colony. Banners read: \"Enough!\" or \"Government Out!\" Demonstrations were held in several other cities including Oporto, Portugal\'s second city, and Faro in the south. Hospitals cancelled non-emergency operations and dozens of kindergartens were closed across the country, union officials said. Just under 80 percent of all public sector nurses had heeded the strike call, according to the General Confederation of Portuguese Workers. The Lisbon metro was closed and train and bus services were disrupted, forcing hundreds of thousands of commuters to seek alternative ways to get to work. Airport operator ANA said 37 flights were cancelled, and dozens of others were delayed. A huge Volkswagen car plant south of the capital decided to halt production for the day but union officials said participation in the strike was much higher in the public sector, which is far more unionised than private industry. The government downplayed the impact of the strike. \"Some Portuguese people did not go to work but there are others who did. The country has not stopped,\" Parliamentary Affairs Minister Luis Marques Guedes told reporters after a regular weekly cabinet meeting. Portugal is struggling to apply radical budget and economic reforms in exchange for bailout loans of 78 billion euros ($102 billion) agreed by the so-called troika -- the European Union, the European Central Bank and the International Monetary Fund -- in May 2011. But as in Greece and Ireland, other eurozone countries that needed a financial lifeline, falling living standards have stoked outrage at the austerity measures. The cutbacks have helped plunge Portugal into recession, with the government forecasting the economy to contract by 2.3 percent this year, while unemployment has shot to a record 18.2 percent. \"The prime minister is the biggest exterminator of jobs,\" said the head of the General Union of Workers, Carlos Silva. The strike comes after auditors from the troika on Monday began a technical review of progress on reforms in preparation for a regular quarterly audit due to begin on July 15.