Looking for John Thomas DUFFY

Looking for Great Grandfather, John DUFFY (Thomas probably added later) supposedly born Dublin, Ireland 17 December 1845 but we have no proof of this birth date - no birth certificate. He died in New Zealand on 15 March 1899. His Death Certificate states he had been in NZ 44 years. We have details of his life in New Zealand from 1868 but we have no information on how he got to NZ, or where he was before 1868. He married Elizabeth BENTLEY in Masterton, NZ, on 31 December 1872 and they had 13 children - all here in NZ. We have traced all 13 families, written a book, held a reunion, and not one of the descendants can add any information whatsoever on how John Thomas DUFFY came to NZ from Dublin, Ireland, and what he did prior to 1868.

We have checked Army Records as we thought he may have come with the British Imperial Army to fight in the Maori Wars, shipping records to NZ and also via Australia. Very difficult to check back into Ireland when we have no parents, siblings etc. We have checked other DUFFY's in NZ but so far no luck finding siblings. I can provide details of the 13 children if anyone needs them. He did join the Masonic Lodge in NZ and at that time they would not admit Catholics, but again we cannot confirm whether he was Catholic or Prodestant. Apparently he was asked if he wanted a Priest when he was dying, but said no. Buried as Anglican. Any help, or direction for further research would be appreciated. Would come to Ireland tomorrow but not until we have some definite information to follow up. Thks.