Time differences between Australia and the stations vary from state to state and also with daylight saving regimes during summer.  The following list indicates the time difference, where applicable, between Australian Eastern Standard Time (AEST) and local time at each station:

Macquarie Island - same as AEST and Hobart time over summer

Casey - 2 hours

Davis - 3 hours

Mawson - 4 hours

To work out the time on station, subtract the appropriate number of hours from Australian Eastern Standard Time.  During daylight saving (in Australia), you need to subtract an extra hour.

Reference: Australian Antarctic Division http://www.aad.gov.au/default.asp?casid=6213