A rise in SA union membership and the proliferation of several new splinter unions have had the unintended consequence of sparking more adversarial labour relations and a rise in unprotected strikes.

Minister of Employment and Labour Thulas Nxesi said South Africa's union numbers grew from 3.5-million members in 2013/14 to over 4-million in 2020/21 and the number of registered unions rose from 203 to 220 over the same period, highlighting vicious competition for recruits in various sectors.

Nxesi was speaking at the Southern Africa Trade Union Coordinating Council (Satucc) worker congress on Friday.

Nxesi read these statistics as a growing trend of unions splintering off due to differences in how they believe they ought to negotiate wages with employers.

The arrival of newer, more militant unions in various sectors also prompted established unions to negotiate more aggressively to take the advantage away from the newcomers. This blunts unity among organised labour, heightening the risk of prolonged, antagonistic wage talks.

Nxesi said that he raised the proliferation of organised labour with unions, suggesting that they find ways to unite all workers, including those in splinter unions.

"One of the unintended consequences of the 1995 Labour Relations Act's freedom of association was the proliferation of trade unions," said Nxesi.

Nxesi said majoritarianism tends to prevent members of splinter unions from being directly represented in bargaining chambers, resulting in a weakened collective representation of workers.

Nxesi said there appeared to be fierce competition for membership among unions, to the point where some used collective bargaining as "recruiting turf", labelling their rivals as "sell-outs" and resorting to damaging strikes to distinguish themselves.

The Department of Employment and Labour's report to the Satucc noted an increase in unprotected strikes and warned that this signalled a deterioration in respect for collective bargaining institutions.

"Even the most militant-sounding union leader understands the importance of registration and can be found lobbying the minister for the implementation of certain aspects of the Labour Relations Act, such as the extension of collective agreements to non-members," the report said.

Nxesi said the department remained committed to finalising the draft National Labour Migration Policy and the draft Employment Services Amendment Bill to limit the number of foreign nationals hired in a business or sector.