Ashwell Prince [ Images ] and Jacques Kallis [ Images ] scored centuries to help South Africa [ Images ] move into a strong position on the second day of the third Test against Australia [ Images ] on Friday.

• Scorecard: Australia vs South Africa, 3rd Test

The hosts ended the day on 404 for three, stretching their first innings lead to 195 runs over the frustrated Australians.

Australia, who have an unbeatable 2-0 lead in the three-match series, were bowled out for 209 on the first day.

The South Africans took advantage of a flat pitch under clear blue skies, with Prince scoring 150 and Kallis unbeaten on 102.

Kallis, the acting captain in the absence of the injured Graeme Smith [ Images ], completed his hundred shortly before the close and made no effort to hide his delight having last reached three figures 13 Tests ago in April 2008 against India [ Images ] in Ahmedabad [ Images ].

Umpire Asad Rauf originally ruled the single that took Kallis from 99 to 100 had been a leg-bye, but later changed his decision to a run after the third umpire confirmed the batsman had hit the ball with a thick inside edge.

The decision led to a brief tiff between the umpires and Australia captain Ricky Ponting [ Images ].

Prince was controversially dismissed after tea when third umpire Billy Bowden overturned Steve Bucknor's [ Images ] not out decision as the Australians appealed for a catch down the leg side, believing the left-hander had got a glove to a delivery from Ben Hilfenhaus [ Images ].