Renting out primary residence then rent somewhere else

If you do all the rental process legitimately and declare the earned rent and keep good records of expenses, then yes: your rental income forms part of your tax return, and all legit expenses can be deducted off the income.

For a very quick and rough calculation:

monthly rental income received on your PPOR
– monthly claimable expenses related to renting (eg management fees, landlord insurance)
– your new monthly rental what you have to pay

if your calculated figure is MORE than 0 then yes, technically you are in a better position, as there is less of your money going into paying off your mortgage. If you then add more of your money into the mortgage so there is more money going in than previously, that will help you reduce your mortgage quicker.

You can claim all deductions the ATO allow for investment properties, but just check with your mortgage repayments as if it was PPOR its quite likely you are paying principal + interest. Only the interest portion of your repayments are claimable. So check what your repayments are, but if you only bought it just over a year ago then the interest portion should still be very high and make it worthwhile.

By the time you add in other deductions and claims, plus depreciation, then it may be negatively geared and can reduce your taxable income.

You’ll need to speak to an accountant in regards to what is required to convert PPOR into IP and what records and evaluation/reports etc are required.

Also have a think about if you plan to return to your PPOR one day and live there again, or if it will remain IP.