"Our main worry is people being able to work and ensuring they can exercise their freedom of association and not be pressured as a result of events," Director General of International Labor Organization (ILO) Juan Somavia said on Tuesday.
Bahrain's unions called a general strike in March to support peaceful protesters demanding an end to the rule of Al Khalifa dynasty.
Saudi Arabia and the United Arab Emirates deployed their troops to the Persian Gulf state to help crush the nationwide protests later that month.
Officials at several firms such as Bahrain Airport Service and APM Terminals Bahrain said that they had laid off more than 200 workers due to absence during the strike.
Meanwhile, state oil company, Bahrain Petroleum Co, later said it had sacked nearly 300 employees.
The ILO denounced the mass sackings and "other repressive measures" in early April.
The UN labor rights agency later sent a high-level team to Bahrain for talks with government officials, as well as worker and employer groups.
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