There were just two buyers competing at the auction, with bidding starting at $2.5m.
Henderson said the new owner was looking to potentially retire to Whitianga.
On the other side of Auckland, at Mangawhai Heads, another luxury four-bedroom home was attracting heat as well. 35 Wharfdale Cres sold under the hammer for $3.1m, more than $1.3m above its 2017 CV.
Bidding for the property started at $1.5m and quickly shot past the reserve price.
The listing agents, Bayleys' Robbie Robertson and Dianne Christensen, said the beach house was "the epitome of coastal living".
The vendors, Greg and Paulene Gordon, had bought the land several years ago and built their dream beach home on it.
The Gordons told OneRoof before the auction that they had partnered with architect Jim Corns to meticulously plot every inch of their new build.
The process, Greg quipped, involved "sending Jim up to the property for a week to get a feel for exactly what was needed".
Christensen told OneRoof last month: "No 35 is an amazing property with wonderful views. The layout of the home is such that it is easy to enjoy whether just yourselves or if the extended family are coming to stay - everyone has their own space.
"A very lucky family will get to make some amazing memories here."
- One Roof