The main highway between Wellington at Kāpiti has now reopened, after multiple slips blocked traffic in both directions this afternoon.
Motorists were asked to expected significant delays after a slip came down at Pukerua Bay on State Highway 59 - formally State Highway 1 - at around 1.25pm.
Heavy congestion remained throughout the afternoon, with stop go traffic management put in place at around 4.30.
Waka Kotahi issued an update just before 6pm to say the road was now open in both directions.
Nearby resident Benedict Knill had wandered down for a look, and said he could see two slips.
"They were just clearing the first, had just finished and this one came down," he said.
"The hill could be unstable. The guy reckons [it will be cleared] after midnight."
Waka Kotahi has advised motorists to avoid the area and delay their journey if possible.
A spokesperson said heavy rain in recent days has made the hills along SH59 unstable, causing slips and debris falling onto the highway in multiple locations.
Contractors are on site cleaning the area, but they said there could be more incidents of debris and slips due to the persistent wet weather and instability of the landscape.
They suspected it would be a number of hours before the road was opened.
Police also advised there is water covering Grays Rd in Porirua, and Paekakariki Hill Rd is also closed due to fallen trees.