Steve Smith has thrown his support behind embattled Australia opening batsman David Warner and predicted a steely reaction following poor form.

Warner has not scored a Test century in his past 27 innings, dating back to January 2020 against New Zealand and is running out of chances ahead of the second Test against South Africa starting on Monday at the MCG.

The 36-year-old left-hander was dismissed for a golden duck in the first innings of the first Test against the Proteas, scoring three in the second innings.

Warner failed to reach a half-century in the recent 2-0 Test series victory over the West Indies too, leading to calls for him to be dropped.

But Australia vice-captain Smith pointed to Warner's 106 from 102 balls against England at the MCG in a one-day international in November as reason for hope.

"You only have to look back a [few] weeks ago, a one-day game out here against England, he scored 100 on what was a pretty tough wicket," Smith told reporters.

"We've seen David when his back's up against the wall, he's done pretty well."

Smith added: "It doesn't matter what format of the game, Davey always plays in a pretty similar way, which has been the beauty of him in Test cricket, being able to take the game on from ball one.

"Sometimes it doesn't work, and he hasn't had a great deal of luck lately."

Australia selection chair George Bailey remained confident in Warner earlier this week, stating it was difficult to glean much from the Gabba Test which was dominated by the bowlers and over inside two days.

"No doubt David would be the first to say he'd like a few more runs and to be contributing a bit more knowing the importance of that role at the top of the order," Bailey said. "But full confidence that will come."