The merger with Ingham Mora, a like-minded, locally-owned business, offered more advantages than bringing a fourth partner in, Mr Wood said.
"From our point of view going from three to nine partners gives us and our clients access to a lot more range of specialisations, in that most partners tend to have a specialisation."
Ingham Mora director Mike Stuart said he had welcomed merger discussions with Wood Walton as there were a lot of similarities between the firms.
"Both of us are not part of the big nationals, we're locally owned and operated so if we want to make a decision, we can," he said.
"By joining two firms together you've got much more resources, you can give a better service to your clients, there are some economies of scale from a profit point of view, but the expertise is probably the main thing.
"We now see ourselves as a big firm with a small firm feel. We have always had a strong people culture at Ingham Mora, both in terms of our internal teams and in our relationships with our clients.
"This won't change with the merger; in fact it will become even more of a focus."
The Wood Walton Chartered Accountants business was started by Alex Sinclair in 1978. Peter Wood joined in 1986 and Andrew Walton became a partner in 1993.
The firm's third partner is Tracey Rae. Neville Watkins retired in January.
Ingham Mora was started by Graeme Ingham in 1965. Mr Ingham joined the national and international practice of Ernst and Whinney in 1984 but in 1991 pulled out and joined sole trader Peter Mora who had an office at Mount Maunganui.
WHK marketing business partner Sarah Dwyer said she believed the Ingham Mora/Wood Walton merger was a sign of the times.
"We have seen accounting firms join alliances over the last couple of years and I think we will see more of this going forward, with the change in the accounting market with cloud accounting and the sophistication of clients you need to be able to have a better service offering for clients to meet their needs which you get with scale."