Four other people have died on New Zealand roads since late Friday night, this latest death being the first today.
NZTA reported the incident south of Foxton - the second serious crash on SH1 this evening - took place at the intersection of SH1 and Newth Rd.
A Fire and Emergency New Zealand spokesman said two appliances had attended the incident, one from Foxton and the other from Waitarere Beach.
He believed people were being extricated from both vehicles and was unsure at the extent of injuries.
Meanwhile, three other people suffered non-life-threatening injuries after a two-car crash blocked SH1 north of Wellington this afternoon.
The incident occurred around 4.35pm near Te Horo with emergency services now on the scene.
NZ Transport Agency said the incident took place near the intersection with Te Horo Beach Rd.
Both lanes of traffic were temporarily closed between Te Horo Beach Rd and Te Hapua Rd. The road reopened in both directions about 6pm.
A Fire and Emergency NZ spokesman said an ambulance and a helicopter were also on the scene.
Police said a diversion had been put in place at Te Horo Beach and Te Hapua. "However, emergency services are working to clear the road and expect it to be reopened soon."