The Sydney-based servers are linked to the existing North American region, meaning players will not have to take any action to begin using them.
The change over is "completely invisible", said Blizzard, "with the immediate benefit of providing a smoother, more responsive gameplay experience."
When Australian or Kiwi players create a game, it will be hosted at the ANZ data centre. When joining a North American game, they will connect to the US data centre.
"We will continue to explore optimal server solutions for all our franchises in each region," said Blizzard.
Diablo III: Reaper of Souls launches next week, March 25, on PC and Mac.