Liz, do you have marriage Certificate in case it has his birthplace on it. I gather his death certificate didn't either.
The other place to determine his place of birth (if military records don't have it) is his shipping records for entering Australia.
the other place you might put an enquiry is on Monaro Pioneers site where Bombala Pioneers and residents are being recorded. He isn't listed there presently but if you put up what you know it grows. i found my great grandparents there and the only branch missing was mine.
I did a quick check in Archives in NSW, Australian and commonwealth war graves to no avail. I hope mike turns up your man in military.
Suzannd (Mackay, Qld)