"We paid a heavy price to be here today. Thousands of comrades have been arrested, but now we get the result of our struggle," he said.
Al Jazeera's Anita McNaught, reporting from Taksim Square, said that in the past, trade unions who tried to hold rallies there in defiance of the ban met with a heavy police crackdown which left dozens injured and hundreds in detention.
"Then human rights and especially workers rights were crushed for years in Turkey," McNaught said.
"Over a series of years, particularly the last three, the unions have steadily pushed and pushed to be reallowed access to back to this square.
"They have said there is no good reason not to allow them back and this year, the government agreed."
More than 22,000 police officers were deployed for the rally and demonstrators went through security checks before entering the square.
Zafer Yoruk, a professor of political science at Izmir University, said the number of workers organised in Turkish unions has fallen dramatically since the 1970s.
"Regarding unionisation and economic rights, I think we're far behind the 1970s," he told Al Jazeera.
"The right to strike, for rights, or solidarity strikes, are totally gone."
Most of the annual May Day marches were peaceful, but in the Chinese territory of Macau police used water cannon and pepper spray against rowdy protesters, injuring at least eight people, including a photographer.
|Clashes broke out in a number of countries
as workers staged rallies [AFP]
Hundreds of thousands of people joined rallies in Europe, many protesting against government austerity policies in the wake of the global financial crisis.
Athens, the Greek capital, witnessed riots, with police using tear gas to disperse demonstrators who threw firebombs and stones in a large May Day rally against austerity measuresneeded to secure loans for near-bankrupt Greece.
In Switzerland, Zurich police used water cannon in an attempt to disperse dozens of stone-throwing protesters as unions and politicians protested against "excessive" Swiss banking bonuses.
In Germany, police said 17 officers had been injured when they clashed with 150 demonstrators who threw paving stones and set garbage cans ablaze in the northern port city of Hamburg.
At least nine demonstrators were detained after the confrontations with police on the eve of Saturday's May Day holiday, the German news agency DDP reported.
Several hundred officers were deployed in the capital, Berlin, ahead of a planned neo-Nazi march and other demonstrations.
The turnout in Cuba was massive, as expected, and authorities claimed the march by hundreds of thousands of Cubans amounted to approval of the island's communist system amid mounting international criticism over human rights.
In Jakarta, the Indonesian capital, thousands of workers marched on the presidential palace, shouting: "Workers unite! No more layoffs!"
| Workers took to the streets to protest labour conditions and demand better pay [Reuters]
Bayu Ajie, a rally organiser, said a free-trade agreement with China had cost jobs, decreased wages and encouraged corruption.
In Russia almost two million people turned out to mark international worker's day.
Demonstrators carrying red balloons, red Soviet flags and portraits of Soviet leaders Vladimir Lenin and Josef Stalin, called for the Russian government's resignation over rising prices and unemployment in Moscow.
Thousands of Cambodian workers marked May Day by marching through the capital to demand better work conditions and the establishment of a labour court.
Thousands of workers in the Philippines also took to the streets to reiterate their call to the government to protect jobs and to safeguard the interests of workers.
In the South Korean capital, Seoul, about 20,000 people gathered to demand better working conditions for labourers and farmers.
In Tokyo and Taiwan, thousands marched for better working conditions and permanent jobs.
In Kuala Lumpur, the Malaysian capital, several hundred workers protested a proposed four per cent goods and services tax. While, in Hong Kong, about 1,000 protesters, including janitors, construction workers and bus drivers, demanded the government introduce a minimum wage of $4.30.
"A lunch box at a fast-food restaurant costs about $4. It's an insult if you can't afford a lunch box after working for an hour," Leung Yiu-chung, a pro-democracy legislator, said on the sidelines of Saturday's protests.