The police serious crash unit, a police photographer, firefighters and ambulance services were called to the scene.
The deaths have been referred to the coroner.
Police said no details would be released until they had been formally identified and next of kin had been informed.
Police closed the motorway while the serious crash unit completed its scene examination.
It was expected to reopen about 10pm.
"Unfortunately two more people will not complete their journey this weekend, adding to the tragic loss of life following fatal crashes across New Zealand," police said in a statement.
"This a timely reminder for all drivers in New Zealand to take care on our roads and drive socially to ensure all road users, drivers and passengers, reach their destination safely."
Any witnesses to the crash were urged to contact Detective Sergeant Craig Johnson on 03 363 7400.
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