Emergency services are responding after a truck rolled over on the Hume Highway near Yass this morning, NSW Police say.
The crash occurred just after midnight tomorrow, about 2km east of Yass Valley Way.
The male truck driver was treated for minor injuries.
The southbound lanes of the Hume Highway are closed between Yass Valley Way and Sheldricks Lane. Northbound lanes are not affected.
Officers from The Hume Local Area Command and the Traffic & Highway Patrol Command are in attendance.
Traffic diversions are in place with all vehicles heading south on the Hume Highway, being diverted along the Federal Highway near Goulburn.
Lengthy delays are anticipated. Police advise motorists to avoid the area or drive with caution due to heavy fog.
Police are urging anyone with information in relation to this incident to call Crime Stopers.