Gas engineers say a new issue has been found at a mains pipe just three months after earlier repairs.
Orsted says it is taking place on Sundays to reduce the impact on traffic.
Police are appealing for information after the collision involving two cars and a lorry on 21 May.
The closure forms part of the ongoing project to dual the road through Norfolk.
The road is expected to be closed for most of the day, police say.
A man being transported by police is jailed after forcing a car to a halt on a dual carriageway.
The weekend closures will allow for work to complete the dualled A47 between Norwich and Dereham.
Norfolk Police has reopened the A47 after an earlier collision involving several vehicles.
The road has been closed for an investigation to take place, says National Highways.
