There are two tax statuses that you can hold in Australia, temporary resident and resident. When you become "resident", you are treated as having acquired assets such as shares and property on the day you became resident at their market value at that time. Take a look here for more information and an example. There is more information on CGT specific to foreign residents here and in the other links on the left.
I hope this helps but let me know if you have any further questions.
Hi.I'm just following up to find out if my answer helped or if you have any further questions.