In a report published on Wednesday, the Belgium-based International Confederation of Free Trade Unions (ICFTU) also said 1,600 trade unionists were attacked and 9,000 arrested.
Latin America remains the most dangerous region in the world to be a trade unionist, with more than 70 activists killed in Colombia last year.
Guy Ryder, the ICFTU general secretary, said: "This year's report reveals deeply disturbing trends, especially for women, migrant workers and those who work in the public sector."
The report criticises anti-union policies in the US, Canada and Australia and condemns the behaviour of multinational companies such as the US-based retailer Wal-Mart and German supermarket chain Lidl.
It highlights the poor treatment of employees working in export goods production zones in Mexico, Bangladesh, India, Pakistan and the Philippines.
The document is also critical of the labour rights records of Middle Eastern states.
Kurt Vannieuwenhuyse, head of union rights at the ICFTU, said: "In some sectors they make up 80% of the workforce, yet they are often denied a passport, blackmailed, and prevented from joining unions."
The body's report says migrant workers, mainly from South Asia, are "shamefully exploited in a number of countries," especially in Libya and Jordan, where unions are either forbidden or subject to severe legal constraints.
In Gulf countries, migrant workers "make up the bulk of the workforce but are weak, vulnerable, mistreated and enjoy few or even no rights," the report said.
Workers have launched a number
of protests in Dubai
The document cites the example of 60 Indian workers in Kuwait who were expelled from the country "for protesting against their miserable conditions and against payment delays".
Foreign workers in the United Arab Emirates have staged strikes to protest against ill-treatment and non-payment of their salaries.
About 130 construction workers there were "brutally attacked for striking" and "some migrant workers have not seen their salaries for as much as 16 months," according to the ICFTU.