People travelling south from Oamaru to Dunedin for the Fleetwood Mac concert on November 18 should factor in some extra travel time.
Strengthening and widening of the Kakaho Creek bridge, 3km north of Hampden, started in March but from November 2 traffic lights will be required at the bridge, meaning traffic delays, the New Zealand Transport Agency (NZTA) says.
Bridges on main South Island trucking routes are being strengthened to take heavier trucks, carrying loads of up to 58 tonnes.
From November 2, contractor Fulton Hogan will begin work which will nearly double the bridge's width.
''It's always been a bit of a tight bridge - reasonably narrow, on a curve - and in the past there have been some quite serious crashes,'' NZTA senior project manager Phil Dowsett said.
''The idea is to widen it and to improve the approaches so that it's safer and feels more comfortable, particularly for large vehicles.''
The bridge was expected to reopen to two-way traffic in December, he said.
