Labour Minister Membathisi Mdladlana has promised "fireworks" over the contentious issue of labour brokers.

"The reality is, labour broking is a form of human trafficking," he told the Motor Transport Workers' Union (MTWU) in Johannesburg on Friday.

"Companies sell the labour of workers to the highest bidder and pay them the lowest possible wage," he said.

No deductions were made for, among other things, the Unemployment Insurance Fund (UIF), pensions, or tax.

"Is this not criminal activity?" he asked.

"I see labour brokers as a problem, and it's a problem that we must work at. We must address this problem and its a battle that we must fight, and its a battle that we must win, and now is the time. Now or never," he said.

Mdladlana told the MTWU ? which is celebrating its 75th anniversary ? that the issue had been under discussion in the National Economic Development and Labour Council (Nedlac) for five years already.

He hinted that action could be announced shortly.