Foreign Minister Stephen Smith has objected to Tim Cahill's send-off in the World Cup, and thrown his support behind the Socceroo's appeal.

Fans were devastated when Cahill, seen as Australia's best player, was given a red card for a late tackle during Australia's disastrous 4-0 loss to Germany on Monday.

Cahill will learn on Thursday if the send-off will cost him a third game on the sidelines, following an automatic one-game suspension.

Mr Smith said he rose at 2.30am (WST) in Perth to watch the game "and like everyone was disappointed".

"I'm never critical of referees, but I did believe that the Cahill challenge was a yellow card rather than a red card," he told reporters during a press conference in Parliament House on Wednesday.

"So we certainly hope his appeal is successful."

A yellow card would have allowed Cahill to remain on the field against Germany.

Mr Smith made the comments during a joint press conference with the Singaporean foreign minister, who appeared bemused by the subject matter.

Mr Smith attempted to rally the nation behind the troubled Socceroos, saying it was a tough pool and there was still time for redemption.

Australia next plays Ghana and then Serbia, needing to win both games to stay in the race for the next round.

"I'm sure they will bounce back in the finest traditions of Australian sporting endeavours," Mr Smith said.

Mr Smith did not comment on traditional sporting rival New Zealand, who fared much better than Australia when they scored a goal to clinch a historic draw with Slovakia on Wednesday.

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