Rob McBride reports from Hong Kong on labour unions staging massive rallies despite new minimum wage law.
Activists have marked international workers' day around the world with marches demanding more jobs, better working conditions and higher wages.
In Athens, Greece's capital, thousands of workers from various labour unions marched down Syntagma Square on Sunday in a demonstration against the government's austerity measures.
Public transportation services were brought to a halt as ship and train crew workers staged strikes throughout the country.
The Greek government is struggling to reduce its massive deficit and debt which forced it to take a $163bn rescue loan from the European Union and the International Monetary Fund (IMF) in May 2010.
One year later, the measures taken have included wage reductions and layoffs, primarily in the public service, and future measures include more downsizing and extending working hours in the civil service.
Al Jazeera's Paul Brennan, reporting from the protests in Athens, said many Greeks have become particularly agitated in the past year as a result of the implementation of the austerity measures.
Costas, a protester who has been unemployed for 10 months now, told Al Jazeera that unemployment is a rampant problem and that the government is trying to enforce too many austerity measures, too quickly.
"Almost nobody has a job right now. Everybody is either earning too little money or is unemployed and the cost of living has risen dramatically over the last year," Costas said.
"Some kind of austerity measures are necessary but the way the government is trying to enforce them is wrong. It is trying to do too much, too fast and the normal people cannot afford that."
In Lisbon, Portugal's capital, pro-labour and anti-IMF demonstrations took place as delegates from the IMF, World Bank and the EU negotiated the terms of a bailout with the government.
Waving banners and flags, the participants called for more jobs, better working conditions and higher wages.
Many are concerned about the economy after Portugal requested a bailout in April as it struggled with high debt after years of poor economic growth and amid forecasts of faltering output.
Al Jazeera's Alan Fisher, reporting from Lisbon, said "the people here want the politicians to know they know that the pain is coming, but they want to be protected.
"The country is looking for a bailout of around $120bn. That is going to mean serious spending cuts and tax rises".
Elsewhere, about 200,000 workers gathered in Istanbul's Taksim Square in the largest May Day rally in the Turkish city since 1977, when 34 people after shooting triggered a stampede. Turkish unions were not allowed back until last year.
In Spain, where the unemployment has reached a euro zone high of 21.3 per cent, several thousand people gathered in the eastern port city of Valencia and condemned the government's failure to create new jobs.
In Moscow, up to 5,000 Communists and members of other leftist groups marched through the city carrying a sea of red flags to celebrate their traditional holiday, what in Soviet times was known as the Day of International Solidarity of Workers.
Since the 1991 collapse of the Soviet Union, the holiday has been known as the Day of Spring and Labour, and organisations from across the political spectrum held their own marches on Sunday.
The dominant pro-Kremlin party, United Russia, gathered the largest crowd by pulling in workers from factories and institutes in and around Moscow. Party organisers claimed that 25,000 people took part.
In South Korea, police said 50,000 people took part in a May Day rally in the capital, Seoul, for better labour protections.
They also urged the government to contain rising inflation, a growing concern across much of Asia, where food and oil prices have been spiking and threatening to push millions into poverty.
Thousands of workers also marched in Taiwan, Hong Kong and the Philippines to vent their anger over the rising cost of living and growing disparities between the rich and poor.
Chinese holidaymakers flocked to Beijing's Tiananmen Square to watch the daily flag-raising ceremony.
In the Philippines, about 3,000 workers demanding higher wages held a protest in a Manila square that included setting alight the effigy of Benigno Aquino III, the Philippine president, grinning in a luxury car.
Aquino was criticised this year for buying a secondhand Porsche in a country where a third of people live on a dollar a day.
In Taiwan, about 2,000 people rallied in Taipei to protest the widening income gap and to demand their government create better work conditions.
About 3,000 people in Hong Kong took part in a Sunday morning protest while another 5,000 were expected at an afternoon rally, local media reports said, citing union organisers.