The circumstances of the crash are not yet known. However, the Serious Crash Unit is at the site carrying out a scene examination.
As a result, SH1 between School Rd and Whakapirau Rd is closed. Motorists are advised there is a detour in place, and they should expect delays or delay their travel times today.
Waka Kotahi NZ Transport Agency reported the serious crash on its social media channels shortly after 6am.
The detour for north-bound traffic is via School Rd, Wellsford Valley Rd and Whakapirau Rd back onto SH1.
The same detour, in reverse, is in place for south-bound traffic.
Road authorities warned that the detour is not suitable for heavy vehicles.
Second fatal crash in hours
The incident comes a few hours after another fatal crash in Takanini, South Auckland, last night.
Emergency services were called to Takanini School Rd about 9pm after reports a car had crashed into a parked vehicle on the street.
"Sadly, the driver of the car - the sole occupant - died at the scene," a police statement said.
The circumstances of the crash are not yet fully known and police are investigating.
