A large slip on State Highway 1 at Ngauranga Gorge has blocked all three lanes heading into Wellington.
The slip struck just as the city was preparing to host the parade to honour Team NZ winning the America's Cup.
All three southbound lanes and two northbound lanes of the gorge were affected by the rockfall. Dramatic dashcam footage captured by motorist Asispal Sandhu shows the moment the slip hit the highway.
Cars were already braking on the busy gorge road as debris starts to tumble down the rockface and spills onto the road.
The footage was published on the Wellington - Live Facebook page.
Police are warning motorists of long delays, saying the rockface will need to be stabilised and the debris removed.
Motorists should avoid SH1, instead head into the capital via Johnsonville or by taking SH2 from the Hutt Valley.
-NZ Herald