The New England highway will be closed to one lane at Glencoe for two months from Monday.
Transport for NSW today described the roadworks as essential maintenance. They will repair the road surface, replace drains and a guardrail.
The works will take about eight weeks, weather permitting.
Work will be carried out between 7am and 6pm weekdays and 7am to 2pm on Saturdays.
Traffic will be reduced to one lane with traffic control and reduced speed limits in place for the safety of workers and motorists.
The upgrade will improve the road's safety, according to Transport for NSW.
Works will begin Monday February 16.