A notoriously dangerous intersection south of Hamilton is being changed into a roundabout.

The New Zealand Transport Agency is building a $4.5 million roundabout at the intersection of State Highway Three and Airport Road.

Highway Manager Kaye Clark said the T-intersection has a terrible crash record.

"Over the last five years, we've had around 24 crashes and five of those were either fatal or resulted in serious injury crashes, so we don't like that."