The one-way system on Quarterbridge Road will be extended to the bottom of Bray Hill from the start of March.
It's been revealed only northbound traffic is permitted on the route and vehicles heading south will be diverted along Tromode Road.
The footpath reconstruction scheme will also involve some road resurfacing work taking place at night time with a full closure.
The work will run from March 1 until no later than Wednesday 31st March.