Sergeant Fane Troy confirmed the fatalities at the scene this afternoon involving two people-mover type vehicles.
The crash, described by a witness as the most serious he's seen in 20 years, happened at the intersection of State Highway 1 and Tutukau Rd about 3.15pm, and blocked both lanes of SH1.
At least three people were trapped with critical injuries, police said, and a rescue helicopter had been called to the scene.
St John ambulance would not comment on the injuries or number of injured involved in the crash, directing all media queries to police.
Local reporter Laurilee McMichael, who was at the scene, said there was a heavy presence of police, fire and ambulance staff. She had seen three helicopters, two of which took off heading north.
"I was told it was a two car head-on at the end of a passing lane."
She said a truck driver recounted that the police told him "it was the worst thing they've seen in 20 years".
Detours were in place, and motorists were asked to use SH5 or SH30 to avoid the scene, or use the diversions suggested:
• Diversion for south to north is at Tirohanga Rd and HS1
• Diversion for north to south is at Oruanui Rd and SH1
There would be significant delays, police said, so motorists were asked to delay their travel.
