South African police have fired rubber-coated steel bullets at stone throwing supporters of the ruling ANC who tried to confront members of the opposition Democratic Alliance party as they marched in central Johannesburg.

Police, who were between the lines of the rival supporters, opened fire briefly at African National Congress (ANC) members clad in the party's yellow T-shirts, a Reuters news agency journalist said.

The supporters of the Democratic Alliance, the main opposition party, said they marched near the headquarters of the African National Congress to demand more jobs.

The South African Press Association said protesters threw bricks as opposition leader Helen Zille was about to address her supporters.

The opposition party members then ran from the scene and police blocked off roads in the area.

South Africa will hold general elections on May 7.

Source: Agencies