Hughes, 20, playing in his second test, hit 115 while Katich struck 108 as the pair put on 184 for the first wicket.

South Africa, though, lifted the intensity of their bowling effort in the second half of the day, spinner Paul Harris leading the way with two for 66.

"Today was special," Katich told reporters. "To get two hundreds and to be able to see Phillip get his first. I said last year he would be a very special player and he started to prove that today. He played superbly and, with the temperament he's got, he's not fazed by anything."

Hughes scored freely from the outset, especially on the off-side, and raced to 75 off 90 balls after Australia won the toss and elected to bat.

Katich accumulated his runs more gradually as the visitors breezed to 119 for no loss at lunch.

Hughes, who also hit 75 in the first test in Johannesburg, moved smoothly into the 90s before two mighty sixes off Harris earned him a maiden test century.

The youngster survived a boot-high catch to first slip Jacques Kallis off Morne Morkel on 114 but eight balls later he mistimed a cut from Kallis to Neil McKenzie in the gully.

Lofted Drive

Captain Ricky Ponting then fell for nine, caught by McKenzie off Harris after a poorly-judged lofted drive, before Katich wafted at a shortish delivery and was snapped up at first slip by skipper Graeme Smith off fast bowler Dale Steyn.

Michael Clarke also missed a straight delivery from Harris as he was clean bowled for three before Michael Hussey (37 not out) and Marcus North (17 not out) put on 37 to take Australia through to the close of play.

With a hot sun burning the clouds away, it was a hard day for the bowlers and they were especially wayward in the morning.

Hughes dashed to his hundred in 158 minutes off 132 deliveries while Katich needed four and a half hours and 177 balls to compile his seventh test century.