McGrath, the provenance of 'Austra-laise' is that it was a poem written by C.J. Dennis, best known for his wonderful collection 'The Sentimental Bloke'. The initial version was entered in The Bulletin's competition for an Australian anthem in 1908 and won a special prize. It was revised in 1914 and widely reprinted. You are quite right - it was sung to the tune of 'Onward Christian Soldiers'.

--Stewie.