Queues of traffic stretching for kilometres are causing lengthy delays for holiday-makers across Sydney and around the state.
A 21-kilometre traffic jam heading west on the Great Western Highway in the Blue Mountains showed no signs of easing by 2pm.
The Transport Management Centre said traffic was also banked up near Wiseman's Ferry in Sydney's north-west, around the fish markets at Pyrmont, on Pennant Hills Road from Carlingford to Normanhurst and on Hawkesbury Valley Way in Richmond.
There was a 2.5-kilometre queue on the New England Highway between Beresfield and Hexham, the TMC said.
On the Princess Highway at Kiama, motorists were facing 90-minute delays due to an 11-kilometre line of traffic.
On the North Coast, the queue was eight kilometres at Macksville, headed north, and five kilometres in the southbound lanes of the Pacific Highway at Ewingsdale, near the turn-off to popular holiday spot Byron Bay.
"Additionally, northbound traffic on the Pacific Highway at Cooperabung on the state's mid-north coast is heavy due to a two-car accident and broken down truck nearby," the TMC said.
"Northbound traffic is queued up to 18 kilometres."
In the Hunter, eastbound traffic on the New England Highway approaching the Hexham Bridge was queued for more than four kilometres at midday, adding an extra 25 minutes of travel time.
At the same time on the North Coast, north-bound traffic on the Pacific Highway at Macksville was queued for eight kilometres, adding an extra 30 minutes to journeys.
Southbound traffic on the Pacific Highway at Ewingsdale was queued for 4.5 kilometres, adding an extra 30 minutes of travel time.
Additionally, traffic on the Pacific Highway at Cooperabung was heavy due to a two-car crash and broken down truck nearby. Traffic was queued up to 10 kilometres in each direction at 12.30pm.