The Greymouth man and his wife were staying at his friends' Marble Court home in the northern Christchurch suburb of Northwood when the massive explosion happened at 10.14am on Friday.
Neighbours and passers-by who pulled stunned survivors from the burning debris were amazed that nobody was killed instantly.
The man and five others were rushed by ambulance to hospital.
His daughter Belinda Blanchfield has been left feeling distraught and worried.
"At this stage, we are very concerned for our families," she told the Herald on Sunday.
Blanchfield said the women are "doing okay" but the families have serious concerns for the men, especially her father who is on life support at Christchurch Hospital.
She thanked everyone for their messages of support and also the "amazing people who helped everyone at the scene".A Canterbury District Health Board spokeswoman confirmed that one person remains in a critical condition.
One person was discharged on Friday, while three others are in a stable condition at Christchurch Hospital. One patient, described as stable, has been transferred to Middlemore Hospital where there is a serious burns unit.
Twelve houses around Marble Court will remain behind a police cordon tomorrow as officers, alongside investigators from WorkSafe and Fire and Emergency New Zealand (FENZ), comb through the rubble for clues. A total of 21 homes have been damaged, with five facing possible demolition.
Chunks of roof tiles, broken glass, pink insulation, and other debris remain scattered over the small cul-de-sac.
Several neighbouring houses have major damage, including blasted walls, caved-in garage doors, smashed windows and eaves.
A gas contractor who worked on the Marble Court house, which was having gas issues, just one day before it exploded arrived at the chaotic scene on Friday and fronted to police officers.
The gas worker voluntarily made himself known to first responders and suggested that police or fire investigators might want to talk to him.
He was devastated by what happened, sources say.
Several Marble Court residents showed up at the police-manned cordon yesterday, wanting to check how their properties coped in the explosion, which caused a blast so big it registered as a magnitude-2 earthquake and which was heard across the city.
They hugged each other, bought each other coffee, and shook their heads in amazement.
"We're all alright and that's all that matters," said Kay Hobson who, with husband Barry, lives two doors down from the main blast site.
The Hobsons wanted to grab some key items from home today, including Barry's medication.Indraj and Akita Fonsaka who live across the road, and whose house was badly damaged, also wanted to get home.
They were waiting for police and fire officials to escort them in.
The Fonsakas had fled with only the clothes on their backs.
Friends and family are looking after them as they said their insurance refused to stump up for temporary accommodation.
Now, their lives have been thrown into turmoil and, like many of their neighbours, are unsure when, if ever, they'll be allowed home.
"We were living very peacefully here," said Akita.
"We have lovely neighbours, it's just a nice quiet street."
FENZ area commander Dave Stackhouse said earlier that it was "probably lucky" the house inhabitants were close to the source of explosion when it happened.
"Often with these types of things it's the blast wave that can kill people further away from the actual radius of the initial explosion," he said.
"So I guess we are lucky that we are not looking at multiple fatalities here."