The table below summarises the plug types, voltage and frequency of electrical current in both Australia and Thailand.
|Plug Types||I||A, C|
|Frequency of electrical current||50Hz||50Hz|
Australia uses Plug Type I.
The voltages found in Australia (230V) and Thailand (220V) are not exactly the same, but the difference is tolerable, so you should not need a transformer.
The frequency found in Australia and Thailand is exactly the same (50Hz). Timing devices and appliances that use motors will function as expected under this frequency.