Australia are in a commanding position in Centurion after South Africa reached stumps on day two of the first Test on 140-6.

The tourists began the day 297-4, but were eventually bowled out for 397 in the afternoon session, giving the Proteas the chance to open their innings in this first Test.

Mitchell Johnson starred for the Aussies as the day progressed after taking the wickets of Graeme Smith, Alviro Petersen and Faf du Plessis with the hosts on 23-3.

Hashim Amla (17) followed his teammates when he was dismissed for an lbw from Peter Siddle, but AB de Villiers and Jean-Paul Duminey steadied the innings by holding off Australia's bowlers.

Duminey eventually fell after taking 25 runs from 48 balls, while Johnson struck again by bowling out Ryan McLaren for just eight.

After a delay due to rain, South Africa closed out the day with De Villiers (52 not out) and Robin Peterson (10 not out) at the crease.