According to the Maxis community manager, "We are in the process of deploying a hotfix to all servers. This includes various improvements and also disables a few non-critical gameplay features (leaderboards, achievements and region filters).
"Disabling these features will in no way affect your core gameplay experience. Getting you playing is our absolute highest priority," the manager added.
In the meantime, Australian players are also having difficulty even playing as the game launched in the region. Maxis promises to add more servers over the next two days.