Contractors have begun work on a nearly five-month strengthening programme at the Maharakeke Bridge on State Highway 2 which will allow it to safely take heavier transport vehicles.
NZ Transport Agency regional transport systems manager Wayne Oldfield said the strengthening work on the bridge, which is just south of Waipukurau, would involve the installation of angle iron beneath the structure.
"In order for this to take place contractors will need to drill 6000 holes for the bolts," he said.
The additional strength would enable "high-productivity motor vehicles" to use the bridge.
As the work would be taking place under the bridge the only sign of activity would be the traffic management along the stretch.