Will an Australian drivers license be acceptable or do I need an International drivers license renting at Noumea Magenta Airport New Caledonia
Your licence is ok, for future reference though its easy to get an IDL:-
You can obtain a downloadable digital copy of an International Driving Licence here:- https://e-ita.org/
You may find it easier to use :- tipoa.org
Do I need an IDL for the Euro car hire option ( as indicated in the Driving License text ) ?
Your licence is in English so you don´t need an IDL. But as I said before, its so easy to get one and its handy for the future.