"I guess it's a little unusual that the new tenant happens to be one of our competitors," general manager marketing Dave Elliott said.
Mitre 10 was keen to retain a presence in Kerikeri, Mr Elliott said.
"We'd like to be able to develop that site sooner rather than later but at the moment our focus is on offering what assistance we can to staff who may not be picked up by the new store management. After 10 years in downtown Kerikeri, it's a big disruption for some of those staff."
Bunnings general manager Jacqui Coombes said the retail giant has had the Bay of Islands in its sights for some time.
"Kerikeri is an area Bunnings is keen to establish in," Ms Coombes said.
It is understood staff now working at Mitre 10 may find ongoing work with Bunnings but they have to re-apply for their positions.
"We will endeavour to provide a seamless transition while the Bunnings rebranding takes place to minimise disruption for our customers," Ms Coombes said.
Kerikeri and Districts Business Association president Jason Vokes said the change was an indication that big companies continued to see the district's potential for growth.
"Bunnings obviously sees opportunities in the North and that's a positive message. I wish Lance [Richards] good luck with what he does next. He's a big employer so it's good to hear jobs might not be lost with this change," Mr Vokes said.
"I think most people were pleased that when New World shifted from that site, Mitre 10 moved in, and now the site will continue to be used. That's always good for a town."
The new 2500sq m store will operate seven days a week.
Since entering the New Zealand market in 2001 Bunnings has expanded to 22 warehouses and 24 stores, with an investment of over $500 million.