The latest game to fall foul of Australia's lack of an adults-only game rating is the upcoming Syndicate reboot, the shooter having been "refused classification" in the country, which effectively bans the game from sale.
While no reason has yet been provided for the refusal, the game has plenty of up-close violence and stabbing and intrusions into people's skull cavities, which if they're graphic enough can cause Australia's Classification Board to say, well, this game is for adults only.
And since there's no adults only video game rating in the country (yet, though it's being worked on), that leaves the game without classification. And a game without classification in Australia can't legally be sold.
So it's not a proper banning, then, but it's the same end result.
UPDATE - Here's why it was refused classification. In short, violence.