Temporary traffic light signals are in operation at Foss Lane, Oldbury-on-Severn after large cracks appeared in the southbound lane.
It is not yet known when works can start.
A South Gloucestershire Council spokesperson said: “Two-way temporary traffic signals are now in use along Foss Lane, Oldbury-on-Severn for safety reasons.
“Road subsidence and large cracks have opened up in the southbound lane and it is imperative that vehicles are now kept off this section of the road for the safety of all road users.
“We will continue to carry out testing to understand the issues and come up with a suitable engineering solution.
“Due to the complex nature of the issues and the deep rhine adjacent to the road, there are unfortunately no current timescales for when these works can be scheduled.
“We apologise for the inconvenience.”