Heavy traffic has been prohibited from using one of the alternative routes between Nelson and Blenheim while State Highway 6 is closed.
Tasman District Council community infrastructure transportation manager, Jamie McPherson, said a considerable number of heavy vehicles using the Korere-Tophouse Rd is causing significant damage to the road surface at a rate faster than repair crews can fix it.
The damage is ongoing and rapidly worsening, creating hazardous conditions for road users.
The council is now prohibiting heavy vehicles from using the road as a through route from this Friday until December 20.
Heavy vehicles may use Korere-Tophouse Road to access properties only where there is no alternative, and if this is the origin or destination for a specific trip.
Traffic travelling between Nelson and Blenheim should use State Highway 6 and State Highway 63 via Kawatiri Junction.