Moore will miss the Serbia game in Nelspruit after picking up yellow cards in both of Australia's opening two fixtures, forcing Socceroos boss Pim Verbeek into changes at the selection table.

Verbeek admitted earlier this week Beauchamp and Milligan were the main candidates to replace Moore, but he hadn't decided on his preferred option yet.

The Dutchman's may consider the threat of Serbia's giant frontman Nikola Zigic, who is the tallest player at the World Cup at 202cm, when he makes his decision.

"They've got a big boy up there and it's going to be tough to go up against him if I do get the chance to go in and mark him," Beauchamp told Fox Sports.

Serbia's threat, though, isn't limited to Zigic's height, with other dangerous outlets including attackers Marko Pantelic, Milos Krasic and Milan Jovanovic.

Beauchamp added: "At the end of the day we've got to get the result and they've got quality players all over the field, so if we go out with the same mentality as we did last game I'm sure we can get a result."

Milligan, who plays his club football for Japanese club JEF United Chiba, said there was plenty of competition for Moore's vacancy, with utility Mile Jedinak another option.

"There are a few other defenders here and we're all obviously putting our heads down and training hard," Milligan told Fox Sports.

"We'll just wait and see what Pim does."

The former Sydney FC man continued the Socceroos were feeling positive after the Ghana game and hopeful of getting a win against the Serbians.

"We've obviously gained a lot of confidence from the Ghana game and a lot of self belief is back," he said.

"We've still got a chance to go through to the next round with our destiny, to a certain extent, in our own hands."