Traffic is "still really heavy" south of Auckland after a fatal crash on the Southern Motorway overnight.
One person died after a collision involving a car, a truck and the median strip on State Highway 1 near Pokeno around 4.35am.
It's the only fatal crash of the Labour Weekend holiday road toll period so far.
However, five people have been injured, one critically, after a head-on crash on SH1 at Paekakariki, north of Wellington.
A woman, who was driving a northbound car, suffered critical injuries. Two others, who were in a southbound car, had moderate injuries - including the driver.
They have all been rushed to Wellington Hospital - the critically injured woman via helicopter, and the other by ambulance, a Wellington Free Ambulance spokeswoman said.
Two others were also injured, but were treated at the scene, she said.
The road was closed between the railway overbridge and Pakakariki Hill Rd, a notorious blackspot.
It was reopened shortly before 2.30pm, and police warned there would be delays while traffic clears.
At Pokeno, the southbound lanes on SH1 were closed between Razorback Rd and Nikau Rd for most of the morning with diversions in place on local roads.
One motorist said she was stuck in an estimated 20km queue of slow-moving traffic on the diversion route.
"I have been queueing for nearly two hours," she said.
The motorway has since reopened, but a New Zealand Transport Agency (NZTA) spokeswoman said motorway traffic was "still really heavy" through to Drury.
A minor crash on the motorway, between Drury and Ararimu Rd, added to the congestion, she said.
"It's still pretty slow going through there, so if people could delay their travel that would be great, otherwise allow plenty of time for their journey."
The NZTA is also warning drivers to expect delays around Greenlane, with the Armageddon expo taking place at the ASB Showgrounds.
The Pokeno fatal crash took the Labour Weekend road toll to one.
The official holiday road period runs from 4pm on Friday to 6am on Tuesday. Last year the Labour Weekend road toll was five, from 94 reported injury crashes.