Drivers and commuters should avoid the area around Gosford High School and Gosford Hospital for 24 hours from 6 pm on Tuesday, December 1.
Traffic at the intersection of Racecourse and Showground Roads will experience major disruptions while a leaking water main under the roadway is repaired.
Work will begin after business hours on Tuesday afternoon and will be completed by 5 pm on Wednesday, December 2.
The water supply to customers will be maintained throughout these works.
Traffic control will be in place and visual message boards will advise drivers on approaching roads to avoid the area.
Central Coast Council apologises for any inconvenience and will continue to inform the community of any changes via media alerts, social media and its website.
Information source: Central Coast Council