The government of New South Wales has a good BMD site at:
http://www.bdm.nsw.gov.au/Pages/family-history/family-histor...The nearest I can find is:
Arthur C Jones, born Petersham, Sydney, NSW in 1885. Father: Frederick C - Mother Mary A E
he appears to have married a Florence E HESSION in 1905???
There are three possible marriage for the son:
Neville John JONES married Loretto Phyllis HEPBURN in 1942, North Sydney
Neville John JONES married Alice Patricia SEERY in 1947, Paddington, Sydney
Neville John JONES married Beverley May DODD in 1949, Chatswood
Without Arthur's parents names you will have virtually no chance of finding them in Wales.
This tree might be worth looking at:
http://trees.ancestry.co.uk/tree/53731019/person/13559432005but these Jones' were English, not Welsh.