The Germans, who were the two-time defending champions, completely dominated the encounter and took the lead in the 11th minute through Jan Schiffer's brilliant field strike.
Leading 1-0 at half time, the Germans then rode on Tim Herbruch's brace (51st, 60th) to take a commanding 3-0 lead which the Australians failed to match.
Earlier in the day, Argentina defeated Spain 2-1 to claim the fifth spot in the tournament, while Netherlands drubbed England 6-2 to finish seventh.
The Argentines took the lead in the in the 51st minute through a field goal from Nicolas Keenan before Tomas Domene (54th) doubled the lead three minutes later from a penalty corner.
Spain, thereafter, pushed hard in search of goals and managed to pull one back through Marc Perellon's (67th) field strike just three minutes from the final hooter.
In the seventh-eighth place classification match earlier in the day, the Dutch scored through Thijs van Dam (22nd), Thierry Brinkman (41st, 68th), Bram van Groesen (56th, 69th) and Morris de Vilder (65th), while Tom Sorsby (55th, 66th) scored a brace for the Englishmen.