A small slip is blocking one lane of State Highway 2 just before the Petone off-ramp near Lower Hutt.
The slip happened around 3pm and is affecting northbound traffic.
"The left northbound lane on SH2 just prior to Petone off-ramp remains CLOSED, due to a #slip," NZTA Wellington wrote on Twitter.
"Northbound queues are currently back to the Ngauranga Interchange, please avoid the area and consider to use SH1 & SH58 as alternative routes."
The slip is expected to cause significant delays.