Roads around the building in Bree street, Johannesburg, were cordoned off and workers at businesses in the CBD watched from a distance.

Songs paying tribute to struggle leaders like Oliver Tambo rang out as the floor boards of the marquee shook with stamping and on-the-spot toyi-toying.

The marquee was draped in the red black and yellow of the National Metalworkers' Union of SA (Numsa), and had chandeliers, draping and air conditioning to keep it cool.

Numsa has described itself as the biggest metalworkers' union in South Africa and has said it has 260 000 members.

It represents workers in the motor manufacturing, electronics, auto tyre and engineering sectors.

The point of the commission is to address concerns over unemployment, deepening inequalities, divisions and cliques, and political problems.

Numsa is an affiliate of the Congress of SA Trade Unions, which is in a political alliance with the African National Congress, of which Zuma is president, and the SA Communist Party.