Foreigners wishing to drive in Cambodia must hold a Cambodian driver licence. You can apply for a Cambodian licence equivalent to your Australian licence in person at the Ministry of Public Works and Transport's main Phnom Penh office or at their outlet located inside Aeon 2 Mall. If you do not have a valid foreign licence you will need to undergo testing to receive a Cambodian licence.
A licence is not required to ride a motorcycle with an engine capacity of up to 125cc. Even if local law does not require you to have a licence for smaller engine motorcycles, we recommend you check with your travel insurer if this will affect your coverage.
At this time International licences are not accepted in Cambodia, however the authorities have indicated this may change in the future.