Hi Onyx
Step 1 - Decision regarding Gift to your son (or his control) or declare Trust (and retain control)
Option 1
So that the transaction be properly documented as a transfer by way of a Gift, it is recommended that you document the transaction in a Deed of Gift.
Option 2
Alternatively, you could retain control of the Property, via a Declaration of Trust, that has yourself or a Trust entity that you control as Trustee, or has you as the Sole Director of a Corporate Trustee, and hold the Property on trust for your son as Beneficiary.
Considerations
There are important considerations between these two options.
The major difference being that a Trust retains control with yourself, and provides a chance that your son will continue to enjoy the benefit of the house, even if he has a marital breakdown, or becomes bankrupt, at some time in the future, whereas a Deed of Gift would provide your Son with absolute control over the Property, to sell it, to mortgage it, etc., and the Property could be lost in a worst case scenario.
A transfer to your son's personal name, or to a legal entity under his control.. may trigger First Home Owner Grant entitlements, stamp duty exemptions... etc, and this also needs to be considered.
Step 2 - Transfer, and registration in the Titles Office
The transfer of title is procedural, and will cost the same regardless of the type of transfer.
Unless a exemption, or concession can be claimed (for example First Home Owner - Stamp Duty will apply).
Kind regards