The A35 Barrack Road is closed between Stour Road and the Fountain Roundabout in Christchurch for urgent gas repair work.
Both lanes of the eastbound carriageway are closed whilst the westbound lanes remain open.
A signed diversion is in place.
In addition, temporary traffic lights are in operation on the diversion route at the junction with Stour Road and Fairmile Road, causing long queues at peak times till January 16th.