Looking for William Mansfield of Belfast Dublin and Timaru New Zealand

Known to have been living in Belfast in 1849, married Letitia Ramsay in Dublin in 1853 and emigrated to New Zealand in 1862, settling in Timaru.

I am trying to find out where and when he was born (probably before 1829, might not necessarily have been Ireland) and where and when he died (possibly in Australia).