Part of Auckland's Southern Motorway is closed after a truck carrying eggs rolled, blocking three lanes.
The crash is causing chaos as Aucklanders leave work early to escape the city for the forecast fine weekend.
The truck ended up on its side across all three lanes of the motorway, but has now been righted, leaving scrambled eggs across the road.
Alistair McNish from U-Sell Park & Sell Yard in Greenlane said a witness told him: "A car cut [the truck driver] off and the truck was about to go over the top of it so he jack-knifed and ended up on his side. His evasive action basically stopped a fatality I guess."
"The traffic can only get by on the strip down the side of the motorway, so it's four lanes down to that little orange strip."
The New Zealand Transport Agency is now diverting motorists off at Greenlane so they can rejoin the motorway after the crash site. The agency advises motorists to delay their journeys or instead use the Western Ring Route through the Waterview Tunnel. Traffic heading east should use Remuera Rd.
Traffic camera photos on the agency's website show a huge backlog of traffic around the SH1 Greenlane interchange and Market Road offramp.
The crash is also causing delays northbound.
The Fire Service said the truck rolled about 1pm. Police say no one is injured in the crash.
Although the truck has now been righted, the motorway remains closed.