The heavy rains in the previous week led to some cracking and rutting on the surface of the new road just south of the Belinda Street intersection.

As a result, the northbound lane was closed and all highway traffic was being directed along the southbound lane under a "stop/slow" arrangement.

Kiama MP Gareth Ward said a new northbound section of the road has been opened to improve traffic flow around the area still under repair.

"Last month, traffic was diverted onto the new northbound lanes at the north and south ends of the project, and now traffic has been diverted to the new northbound lanes south of Belinda Street," Mr Ward said.

"Roads and Maritime worked with the Environmental Protection Authority to allow work to be carried out around the clock to ensure the new northbound lanes could be completed ahead of schedule.

"The traffic has now been moved to the new northbound lanes much earlier than anticipated, which is great news for motorists and the community."

He said work to build the new southbound lanes has started and would be carried out between 7am and 6pm weekdays and 8am and 1pm on Saturdays.