Ryan donned a korowai supplied by an elder of the Ngati Kahungunu of Hawkes Bay – and delivered his opening remarks in Irish and te reo Maori.
“I am conscious that we are indeed fortunate to enjoy special ties of kinship and history with New Zealand and with the many New Zealanders of Irish heritage,” said Ryan.
“I am deeply honoured to have been given the privilege of representing Ireland as the first resident ambassador to New Zealand.
“I am particularly mindful today of the rich contribution of generations of Irish women and men to the development of New Zealand, and their love of both countries.”
There are more than 10,000 Irish-born citizens in New Zealand.
Irish president Michael Higgins revealed the opening of the new Embassy in Wellington during a visit to New Zealand last year.