Video footage showed a plume of black smoke filling the sky, with huge flames coming out from the roof of the building, reports BBC.

President Cyril Ramaphosa visited the scene and called it a "terrible and devastating event", the British media reported.

The building's sprinkler system had not functioned properly, he added.

Dozens of firefighters reached the spot and are fighting to bring the flames under control.

The fire started just a day after Archbishop Desmond Tutu's state funeral took place at St George's Cathedral which is located near the parliament.