Hi lnr,
The NZ Society of Genealogists has a Pedigree Collection entry for Michael RODDEN, Place Clonfert GAL IRL. Date: c'1865. Record Type: Birth. REF: PED711097
I suggest you contact the NZSG because it seems likely that descendants may have done research on the family and may still be around.
You might also consider contacting the Otago Settlers Museum (google search) as well.
regards, riley