Charlene Phuong, 23, and her 44-year-old mother-in-law Fay Leota were on a family trip from Dunedin to Queenstown on October 23, 2021, when Hayden Manoah, who was 17 at the time, hit them head on.
Both women died at the scene in front of horrified family members who were travelling through Waihola in convoy.
Coroner Mary-Anne Borrowdale issued a notification this month that no inquiry would be opened into the deaths.
"On the basis of the available information, I am satisfied that all of the matters ... have been established to the extent that they can be in the course of the criminal proceedings.
"I am satisfied that there are no circumstances relating to this death that make an inquiry necessary or desirable."
Manoah had been warned in the past that his driving could result in tragedy.
On the day of the fatal collision he was driving a Subaru Impreza after having spent 10 hours on the road the previous day in breach of his learner licence with minimal rest.
Manoah was driving "sharp and erratically", the court heard, tailgating another vehicle, and repeatedly veering across the centre line, looking for opportunities to overtake.
Just south of Waihola he pulled into the path of an oncoming vehicle, which had to suddenly swerve to avoid colliding with him.
Behind that car, Ms Phuong, driving a Nissan Tilda rental, was unable to take evasive action.
A post mortem found she died from cranial trauma while Ms Leota sustained massive abdominal and thoracic trauma.
At the Dunedin District Court in September last year, Manoah was sentenced to six months’ community detention and two years’ intensive supervision.
He was banned from driving for four years and ordered to pay $2000 to the victims’ families.
