Johannesburg - Former Cosatu general secretary Jay Naidoo was arrested in Swaziland on Thursday, a spokesperson said.
"He was in Swaziland to investigate worker rights violations," said Congress of SA Trade Unions spokesperson Patrick Craven.
The International Trade Union Confederation said in a statement that Naidoo was to chair an international panel of experts about labour rights violations affecting their lives, on September 6.
Panellists were expected to hear directly from workers about how labour rights violations affected them, to present their findings after the hearing, and to identify from where the attacks came.
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