Effective Tuesday, only small vehicles will be allowed to use the Schoolhouse Corner to Shrewsbury Road from the Ring Intersection in Portland.
The National Works Agency (NWA) says the restriction is due to work being carried out on the road to facilitate the construction of a retaining wall and the replacement of a culvert.Restricted access to the road will remain for three weeks.
The alternative route is through Rock Hall
A section of the road was damaged by flood rains last October, resulting in single lane access.