Symptom
The time zone you need does not appear in the Date & Time preference pane.
Australia has a large number of time zones in use during the transition from standard time and daylight savings time, particularly since states and certain locations change on different dates. The transition typically spans a month. Incorrect time settings can contribute to incorrect behavior of email, paging services, and some network backup solutions.
Solution
The information for all time zones in Australia is contained in the files at:
/usr/share/zoneinfo/Australia/
The contents of these files is in binary format, but their names are locative in nature. For example, the "Darwin" file contains time zone information for Darwin and the Northern Territory; and "Broken_Hill" for the Broken Hill Region. You should not attempt to edit, rename or modify these files. If you list the contents of the directory, you will see these names:
H2N2079P2:share/zoneinfo/Australia] mdh% ls
ACT Canberra Lindeman North Sydney Yancowinna
Adelaide Darwin Lord_Howe Perth Tasmania
Brisbane Hobart Melbourne Queensland Victoria
Broken_Hill LHI NSW South West
You should decide which locality's file you need to use before continuing.
The symbolic link /private/etc/localtime is set to point to the appropriate zone file for time zone information. Normally, this link is set automatically from the Time Zone section of the Date & Time preference pane. If your time zone or locality is not shown there, the following procedure can be used to set the system's time zone correctly:
1. Open Terminal (/Applications/Utilities ).
2. At the prompt type :
sudo ln -sf /usr/share/zoneinfo/Australia/Darwin /private/etc/localtime
Note: This example is for Darwin. For other locations, substitute the name of the file that matches the desired locality. Note the space that is between Darwin (the locality name) and "/private/etc/localtime". Be sure to maintain this space when you type the command for your locality.
3. Press Return.
4. Type your Admin user password when prompted, then press Return.
5. Quit Terminal
This document will be updated as more information becomes available.