The marriage certificate in Tasmania should hopefully contain his parents names
I would contact the following:- Tasmania Registry BDM to see if that information is contained generally in their marriage certificates.I know it is in other STates, but have never had to purchase one from Tasmania- so really do not know the answer.
The numbers for the purchase of a certificate etc are contained at the end of my reply
Also, if he died in Victoria- then hopefully his parents should be included on his death certificate I hope this is some sort of help
Digger - 19 Tasmanian Pioneer Index 1803-1899
Surname: JACKSON Given Names: GEORGE THOMAS Event: Marriage Father/Spouse Surname: SHAW Mother/Spouse Given Names: CATHERINE Day: 04 Month: 3 Year: 1873 Age: 18 Sex: M Spouse Age: 21 Spouse Sex: F Registration Place: HAMILTON Registration Number: 138/1873 Reference: RGD 37