The Wellington Anglican Diocese extends from Ohakune to Wellington and across to the Wairarapa.
An assistant bishop - Wellington's first woman in the role - is to stay in Wellington. The Rt Rev Duckworth will look after the northern parishes.
He intends to stay mainly in Whanganui at first, and keep a low profile.
"I'm coming into this wonderful town to find out what God is doing here already. I'm not riding in on a charger. I'm coming to join with what's already happening."
He won't be a "stealth bishop" or a "ninja bishop" but wants to begin by listening, learning and watching. He's already preached one Sunday sermon at Christ Church.
"I think I'm preaching this Sunday, so that will be fun."
The consolidation of Whanganui's four parishes into one was a courageous move, he said.
"Full credit to the courage of the people. They have tried to strategically wrestle with what does God require of them in Whanganui, and how should they structure themselves going forward."
The change is a "pruning" that will make way for new growth. He feels an energy at Christ Church on Sundays - "a sense of God doing something".
"Those courageous moves lay a platform for them to rebirth in different ways and shapes that haven't be tried before in Whanganui."
Older people in the church may not like change, but he said they know it is needed.
"Every generation has to re-imagine the church, but also hold true to its DNA."
To a younger generation an Anglican bishop in full regalia looks like "batman in a funny hat", he said. But the clothes are symbolic and when people understand that they have meaning.
He expects people to look beyond his dreadlocks and bare feet and not "judge a book by its cover".
"My hope would be that it's not the appearance but the content that really matters."
Before the Rt Rev Duckworth was made a bishop he was a priest, but without a church to look after. He earned money by training people in youth and community work.
He lived with people of all ages in a contemporary monastery on the Kāpiti coast for 11 years.