A spokesperson for Attorney-General Philip Ruddock told ZDNet Australia the game -- Postal 2: Share the Pain -- had not been put forward for assessment by the Office of Film and Literature Classification, meaning it "cannot be legally sold or hired in Australia".
Reports from New Zealand said the country's censor had banned the game, determining its availability to be "injurious to the public good".
The game allows players to control a character called Postal Dude who assaults other characters in a variety of ways, including kicking them, killing them and mutilating their corpses. The classification office also said "visual and vocal references throughout the game reinforce callous racist, sexist and homophobic stereotypes..."
Only a small number of copies of the game were in circulation in New Zealand, none of which were available through commercial outlets in the country.
Both Australia and New Zealand earlier this year banned the game Manhunt, the Australia's Office of Film and Literature Classification revoking the game's MA15+ certificate after an appeal by Ruddock based on a complaint by Western Australian Justice Minister Michelle Roberts.