It appears the vehicle partially mounted a roadside embankment before flipping back onto the road on its side.
No-one was injured in the accident but at 9 o’clock this morning southbound traffic was still backed up past the Mullumbimby turnoff.
Motorists are being diverted via the Old Pacific Highway and trucks coming from Queensland are advised to take the New England Highway.
The southbound lane is expected to remain closed for most of the morning.
The accident came just hours before the northbound lane of the Banora Point bypass was declared open to traffic.
Federal transport minister Anthony Albanese, member for Richmond Justine Elliot and Tweed mayor Barry Longland were visiting the site at 9 o’clock this morning.