Hi nakshar,
The double taxation agreement between the UK and Australia does not allow relief for 'trivial commutation lump sums' (taking out the whole fund as one payment).
This means that you will pay tax on the pension in Australia, if you take the whole amount out.
It would not be taxable in the UK.
If not taken as a trivial commutation lump sum, any payment received from the pension would be taxable in the UK and not Australia.
You will need to consider the rules for the remittance basis as you may find that claiming the remittance basis more costly than declaring the pension.
Residence, domicile and the remittance basis: RDR1
Thank you.