The Illawarra Highway is closed in both directions at Macquarie Pass after a truck rolled over on a hairpin bend near Mount Murray Road.
Motorists should use Picton Road as an alternative, as Jamberoo Mountain Road is still closed due to a landslide at Knights Hill.
The diversion is suitable for all vehicles.
Motorists should prepare for delays and allow additional travel time.
It's not known when the Illawarra Highway will reopen.