Eurobodalla Shire motorists will face at least a two hour extension on their trips to Canberra as Transport for NSW prepares to close the Kings Highway over the Clyde Mountain for almost two-and-a-half months.
Workers will remove unstable trees from the roadside beginning on August 30, with works expected to continue until at least the middle of November.
Transport for NSW's regional director for the south, Sam Knight, said the Highway would be closed from River Forest Road to Misty Mountain Road from Monday to Thursday between 8am and 4pm.
"An arborist report identified approximately 400 high-risk trees on the Clyde Mountain section of the highway which were badly burnt in the 2019/20 bushfires," she said.
"These trees have become more unstable due to subsequent storms and flooding, and will be removed as they pose a safety risk to road users.
"This work must be carried out under full road closure of the Kings Highway during the day as there would be an unacceptable safety risk if the work was carried out at night."
The road will be open from 4pm to 8am from Monday to Thursday, but will also remain open on Fridays, Saturdays, and Sundays, as well as public holidays and school holidays to ensure high volumes of traffic aren't negatively affected.
Ms Knight encouraged drivers to plan ahead.
"The benefits of an eight hour full road closure include work being completed more efficiently and in a shorter timeframe," she said.
"Closure times have been determined in consultation with Eurobodalla Shire Council and aim to balance minimising disruption to motorists with the need to safely and efficiently carry out the work.
"Alternative routes will be available via the state and regional road network, and Transport for NSW encourages motorists to travel outside of the closure times or plan their journeys in advance."
The alternate northern route would involve driving up the Princes Highway until the Turpentine Road turnoff, then rejoining the Kings Highway past Braidwood, an additional two hours of travel time.
The alternate southern route is worse, as the route via the Princes Highway, Snowy Mountains Highway, Monaro Highway, and Kings Highway would add about five-and-a-half hours.