Hi There
This is not professional advice, but, what you are seeking to do in my expierence is not possible. It is the purpose of the origional loan which determines that it is tax deducible or not. You may be better of selling your current home and using a cash deposit (as much as you can afford) to buy your new home. Then, you take out a new LOC (line of credit) secured against the new house, and these funds can be used for purchasing new investment properties…or as the deposits and costs ie stampo duty ect)
This is the advice I have personally recieved from accountants in the past (regarding the tax side) but you should get your own independant advise.
sorry probably NOT what you wanted to hear.
Cheers
Maggie Smith

Hi There

Its Maggie Smith, from Ripe Property finance in Perth here, (licenced broker since 2002) could you please tell me how much your investment property got valued for (or your estimated current value), and what the current debt that you took out to buy the investment property is a present.
The main risk of seperating the securities as I see it is that if the current value of the investment property debt as a percentage of its value is over 80% then you will have the cost of mortgage insurance to pay…even if the loan is increased to cover it it is still a cost you eventually need to pay or need to pay interest on.
If you give me the figures, I will look at it for you and let you know. Is the loan full doc?? Lo doc you will be charged mortgage insurance over 60% LVR with Homeside

Cheers
Maggie