The leaders Cosatu and the ANC elect at their upcoming congresses must be able to get South Africa out of its economic woes, Cosatu general secretary Zwelinzima Vavi said on Tuesday.

"So, we elect leaders that have capacities to take us into a different direction... where we can begin to address the economic challenges that we are facing," he said.

The Congress of SA Trade Unions (Cosatu) holds its national congress next month. Its alliance partner, the African National Congress, has its national conference in December.

Vavi told businesspeople in Sandton that strong leaders were needed because South Africa found itself in "not a very nice place" politically, socially, and economically.

The killing of 34 workers at Lonmin's platinum mine in Marikana was "a statement about the worst that can come out of the current social and economic environment".

"A growing number of South Africans feel left out," he said.

Vavi warned that the Marikana incident threatened "some form of implosion".

"The demands that these workers are making cannot be dismissed."

Vavi said one of the biggest lessons from Marikana was that the trade union movement also had weaknesses.

One of these was the gap between union leaders and members.

He said it was an issue that every single general secretary of a union stayed in a formerly white suburb, could send their children to good schools and had access to private healthcare.

Another weakness was the distraction of divisive politics.

"There is a degree of unions not focusing on workplace issues and carried by the factional battles in the ANC for positions.

"... There's a possibility for everybody to move up... and that tends to make people sometimes to cultivate that possibility instead of cultivating the better environment for the constituents that elected them."