The Jackadgery Bridge on the Gwydir Highway will be closed to all traffic overnight from 6pm, Friday, April 4, for essential repairs.
It reopens to heavy vehicles at 9am the next morning when the bridge will operate under single lane closures with alternating stop/slow arrangements and a 40km/h speed limit, weather permitting.
Transport for NSW said an overnight closure is required to allow concrete to cure and reach minimum strength before carrying vehicles.
Motorists and freight operators are asked to avoid nighttime travel on the Gwydir Highway during these dates due to lengthy detour times.
Vehicles travelling north will be detoured via Clarence Way and the Bruxner Highway to the New England Highway. Vehicles travelling south will be detoured via the Pacific Highway and Waterfall Way to the New England Highway.
The bridge closure is part of ongoing essential bridge maintenance work that started in late-January.
A second overnight bridge closure will be carried out late May or early June.
For the latest traffic updates download the Live Traffic NSW app, visit livetraffic.com or call 132 701.