Lukas Podolski and Miroslav Klose both found the net in a first half that Joachim Loew's side dominated.
And when Australia's Tim Cahill was sent off just before the hour mark Germany were able to add two more through Thomas Muller and substitute Cacau.
Australia coach Pim Verbeek had named a cautious starting line-up featuring not a single recognised striker.
Yet the Socceroos almost took an early lead as Germany failed to deal with a corner.
Richard Garcia, the Hull City midfielder, fired in a shot from close range but Germany captain Philipp Lahm was in the right place to block.
Australia goalkeeper Mark Schwarzer then had to parry a drive from Klose at the other end but the Fulham man was soon picking the ball out of the net.
Podolski's emphatic finish gave Germany an eighth-minute lead after Muller had cleverly pulled the ball back from the right.
Schwarzer managed to get a glove on it but with the ball travelling at 82 miles per hour it still flew in.
Podolski set Klose up for what looked an easy finish but the Bayern Munich man somehow managed to slice wide from six yards.
But he made amends straight away by heading home the second in the 27th minute when he beat Schwarzer to Lahm's lofted ball into the box.
Lucas Neill hooked away a goal-bound effort from the excellent Mesut Ozil and there were a few more close shaves for the Socceroos before the half-time whistle.
Any hopes Australia harboured of making a memorable comeback evaporated in the 56th minute when Cahill was shown a straight red card for a tackle from behind on Bastien Schweinsteiger.
From then on it was merely a matter of how many more Germany might add and Mueller made it 3-0 in the 68th minute with a calm finish inside the box.
Substitute Cacau, who had just come on for Klose, wrapped up the scoring three minutes later.