Her father, David Crowley said: "Their last moments, did they have any?"
Family friend Donna Northcott said the children's father was "a ratbag with a heart of gold...so in love with the kids".
"Just before Christmas and with a new baby, they should have been celebrating."
Residents of Whakamaru were also coming to terms with the news.
Lynette Thompson, whose brother lived opposite the family, said the couple had "good personalities''.
"They sort of stuck to themselves. They were quiet.
"She seemed happy-go-lucky with her wee one,'' said Mrs Thompson.
The pair had been together about four years, she said.
Eleven-year-old Jordan lived with his mother and was believed to have come to stay with the couple for the school holidays, just before the day of the crash.
The family may have lain in the wreckage since Sunday night.
They were last seen at their home in Whakamaru at 8pm on Sunday. It is not clear where they went and when they crashed.
Post-mortem examinations are to be carried out to determine whether they died instantly or while trapped in the car.
"Their vehicle appears to have been heading towards Whakamaru, suggesting that at some stage they had left the settlement to an unknown destination and were then returning,'' said police spokeswoman Kim Perks.
The car had left the road and rolled down a bank, the force of the impact wrapped the car around a tree about 20m from the road, said police.
It was found wrapped around a tree by contractors working at a forest area on State Highway 32 near Whakamaru.
Taupo police area commander Inspector Steve Bullock this morning said the family were well known in that small community.
"They have extended family in Taupo, Tokoroa and Mangakino, all townships nearby,'' he told Radio New Zealand.
"It's always a tragedy when a whole family passes like this, and especially close to Christmas, which is a time when we all reflect on our own lives and our own family. It is very traumatising for all involved.''
Mr Bullock said the focus of police inquiries was to establish exactly when the crash occurred and urged anyone with information to come forward.