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Due to Rolleston's condition, a specialist paramedic was flown in to stabilise him, BayTrust Rescue Helicopter said.
Rolleston was then flown to Tauranga Hospital.
A second person in the car had minor injuries.
Tauranga Boys' College principal Robert Mangan said he "expressed his best wishes to James for a hasty recovery".
Mr Rolleston was a student at the college for most of his Year 10.
"We're hopeful he makes a quick and full recovery," Mr Mangan said.
Mr Mangan said it had been a big deal to have the star of Boy at the school.
"He kept a low profile, he didn't make a big scene of having been in that role.
"He wanted to be treated as a normal student."
He said the school had been disappointed Mr Rolleston headed away, saying it would have been nice for him to stay at Tauranga Boys' for the duration of his schooling.
Tauranga charitable trust Homes of Hope, who Mr Rolleston has spoken for, would be sending flowers and the children would be making a card for the 19-year-old.
Tributes and goodwill messages flowed to Rolleston online.
Boy co-star Cohen Holloway wrote on Facebook: "Thinking of you cuz. Hope you all good".
Brooke Rolleston said: "Hope your all good cuzz", while Caleb Kingi added: "Feel for the bro hope you make a good recovery my bro".
Kiwi pop star Stan Walker turned to Instagram to say that Rolleston "needs our prayers".
"Please everybody pray for our bro @jamesrolleston right now ... He's been in a massive crash & needs our prayers ... Jesus take care of him & also bring peace & strength to his whanau ... Kia kaha brother ... "
Vodafone NZ today wished Rolleston, who stars in its commercials, a "very speedy recovery".
"James Rolleston is a hugely talented young man, who we've been lucky enough to work with over the years," it said.
"We were saddened to hear of his accident last night, and all our thoughts are with James and his family."
Rolleston is awake and is surrounded by his family, agent Tim Gordon confirmed.
"At the moment, he is in a holding pattern. He's alright," Gordon said.
"They are making him comfortable and he is responding to all the things he needs to respond to."
Wellington-based Gordon said he is hoping to travel to Tauranga soon.
He is getting updates from the family who told him it was a "reasonably serious car accident".
Gordon said he didn't know if Rolleston had been a passenger or whether he was behind the wheel at the time of the crash.
Rolleston attended the world premiere of his latest film The Rehearsal at the New Zealand International Film Festival in Auckland on Saturday.
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He is starred in a remake of Goodbye Pork Pie in which he has performed some of the stunt driving for the car chase movie.
"He's actually an amazing driver," producer Tom Hern told the Herald during the shoot.
"The stunties were blown away by him. We thought we would have to have stunt doubles do most of the driving but he's ended up doing quite a lot because he's a natural talent and a cool head."
Rolleston made his screen debut in Taika Waititi's 2010 film Boy, playing the main role of the child who idolises his father.
In 2014 he was in two further films - The Dark Horse, in which he co-starred opposite Cliff Curtis as a teenager who is set to be initiated into a gang, and The Dead Lands, in which he plays a young Maori warrior seeking vengeance for the massacre of his family.
Family friend Barry Howe said James Rolleston was a "really good friend" to his son and word of the crash had spread quickly in the community.
"He's a good boy, bit of an icon in our little town. He's really down to earth. He still plays rugby when he comes down. He played two weeks ago.
"All of our hopes and wishes are out there for James' recovery. All the boys are a bit devastated, all rooting for him for a speedy recovery."
Bay of Plenty District Health Board released a short statement, which said: "Actor James Rolleston, 19 years old from Opotiki, was this morning airlifted to Tauranga Hospital following a car accident. No further details will be released and the family will not make any comment."
- Additional reporting Kyra Dawson, Anna Whyte & Allison Hess
