Stock losses, I presume you are referring to loss on shares. Generally speaking the losses on shares are capital losses and as such you cannot take a deduction for that. If you have a capital gain you can set it off against that and if not you will have to carry forward the loss until you have a capital gain.

Australian residents for tax purposes need to declare their world wide income in their tax returns and therefore if you are a tax resident you can set off overseas capital losses to capital gains.

I hope this helps.

Mitesh Modi CA