Zip code in search form

This happens because zip codes like 2000 are used in other parts of the world as well, and sometimes Google assumes you are searching for location in the wrong country. So it will find the 2000 zip code, but instead of it being in Australia, Google will assume you want the one in the US.

To fix this you can restrict the searches to a specific country. You can do this on the settings page in the “Google Maps API” section. Set the map region to Australia, and tick the checkbox that shows up next to “Restrict the geocoding results to the selected map region?”. This should fix the problem.