A traumatised Martinborough family who endured the death of their 3-year-old daughter last month are now watching her twin sister undergo repeated surgery after suffering burns to 50 per cent of her body.
The 3-year-old is believed to have been playing with matches or a lighter at home when she accidentally set fire to herself on Monday afternoon.
A Wellington Free Ambulance team treated her at the scene and drove to Featherston Domain to meet Life Flight's Wellington-based Westpac rescue helicopter.
She was transferred to Hutt Hospital, then taken on a 70-minute Life Flight air ambulance flight with a medical team to Middlemore Hospital in Auckland.
Hospital communications spokeswoman Lauren Young says the girl underwent surgery yesterday and was "critical but stable".
The girl had a twin sister who died of natural causes last month.
Ms Young said the family is "absolutely traumatised" and did not wish to speak to media.
She said with burns a person can have surgery "every couple of days".
Featherston fire station officer Colin McKenna and his crew prepared the Domain for the helicopter's arrival and transferred the girl from the ambulance to Life Flight.
He said the girl was conscious and sat up to look at the helicopter as they transferred her.
Asked why the helicopter did not go all the way to Martinborough, Mr McKenna said "your guess is as good as mine" but noted there were very high winds.
"The pilot did a really great job, it was really howling."
Wellington Free Ambulance spokesman David Baker said their team was first on the scene but would not give details of what happened.
"It was a very serious [medical] incident for a child of that age," Mr Baker said.
The girl's mother is a teacher at St Teresa's School in Featherston.
School principal Frazer Mailman said the girl's twin sister passed away at Starship Hospital earlier this month.
"For this to happen to the other twin [is] terribly sad for them all," Mr Mailman said.
"They had her funeral three or four weeks ago."
He said the family will need space.
"People have got to appreciate these are tragic circumstances."