Holiday-makers returning to the big smoke are leaving a trail of fumes north of Auckland in traffic delays of up to three hours.
Police said State Highway One was experiencing larging than usual volumes of traffic.
Motorists and their passengers are venting on social media about the hold-ups.
Said Waimarie Ratu: "Traffic from Tehana to Warkworth moving at snails pace."
Angie Calver posted on Facebook that there was hope for long-suffering road-users: "So after three hours on the road we are past warkworth and its like there was never any traffic!"