State Highway 2 between the Hutt Valley and Wairarapa has partially reopened after a serious crash closed it for about four hours this afternoon.
The crash between a motorcycle and a car happened about 2.30pm on the road between Kaitoke and Featherston north of Wellington, police said.
A Transport Agency Waka Kotahi spokesperson said no detours were available and motorists should delay their journey.
The road was still closed at 6pm, but partially reopened before 7pm.
The Serious Crash Unit was onsite, Waka Kotahi said.