SYDNEY, AUSTRALIA - JANUARY 06: Usman Khawaja of Australia celebrates his century during day two of the Fourth Test Match in the Ashes series between Australia and England at Sydney Cricket Ground on January 06, 2022 in Sydney, Australia. (Photo by Cameron Spencer/Getty Images)

Australia are set to continue batting on Day 3 at the Sydney Cricket Ground during the third and final Test against South Africa.

The Australians went to stumps on Day 2 at 4 for 475 after bad light and rain once again stopped play.

A total of 57 overs have been lost so far, and with more rain forecast on Day 3 and 4, albeit with 98 overs scheduled per day rather than the usual 90, it's beginning to appear like Australia's best chance of winning - and securing their spot in the World Test Championship final - is to go as large as possible in the first innings.

Usman Khawaja, who is 195 not out, will be joined at the crease on Day 3 by Matt Renshaw, while Alex Carey and the bowlers are still yet to bat.

It follows Steve Smith's century and Travis Head's blitz on the afternoon of Day 2, with the Australians once again moving into a commanding position, as they did in both Brisbane and Melbourne during the first two Tests of the series.

The follow on is a rarely used tactic in the modern game, however, with only two quicks and a majority of overs to be bowled by spine, it would appear Australia could elect to enforce the follow on in this game.

"If we can bat pretty big in this first innings it can give us some options potentially," Steve Smith said after the day's play.

"It seems like it rains all the time here for Test matches, which isn't ideal when you have a dry surface and you want that spin and reverse swing coming into play."

Smith said the pitch is beginning to show more signs of life.

"There is starting to be a little bit more going on there," he said.

"That's certainly positive signs for us. And the rougher and more abrasive that surface gets, the more you'll probably see reverse swing come into play.

"Our bowlers have bowled really well throughout this whole series so far. I expect nothing different."

Play on Day 3 gets underway at 10am (AEDT).