The explosion on Friday left six people injured, obliterated one home and damaged 20 others including five that were severely damaged by fire.
One person is in a critical condition and three others are stable at Christchurch Hospital. Another person is in a stable condition in Auckland's Middlemore Hospital.
Witnesses said damage could be seen up to 100 metres away, and police evacuated about 50 residents from their homes.
Canterbury metro commander Superintendent Lane Todd said at least five homes would be uninhabitable as a result of the gas blast.
Fourteen homes remain off limits.
"Police, WorkSafe and Fire and Emergency investigators are continuing to examine the wider scene but also the house itself, that work will continue today and we expect that work to finish by late Tuesday afternoon."
Evacuated residents of Marble Court were yesterday escorted to their properties by police to collect belongings as they waited for engineers to decide whether they would ever be able to live there again.
Indraj Fonseka and his wife Amita were the first people to own a home in the Northwood subdivision, building their Marble Court home in 2009.
They were at both inside on Friday morning when the house across the road exploded.
Fonseka said the noise was like nothing he'd ever heard before, and as his wife screamed he had no idea as to what was going on.
"We didn't know, we first thought that this explosion was within our house, but then I came out to see that there's a fire going on in front of house.
"I realised that the whole neighbourhood has been affected."
The couple's house was significantly damaged. To make matters worse, they had only recently finished their EQC repairs.
Fonseka is still not sure whether the house is salvageable, but had already told his insurer he wanted out.
"I have actually spoken to my insurance company and told them I would rather go for a settlement so that I can move on.
"They said that I did have that option."
The Fonseka family will stay with friends until they can find somewhere more suitable to rent.
One resident who has been allowed back is Air New Zealand operations controller, Jeff Gin.
Gin was working at Christchurch Airport, 8km from his home in Northwood, when he heard a great bang.
"The children were fine, they had a shock but they thought it was a thunderstorm, so we just played along with that and said that we are going over to see grandma and granddad."
Gin and his family live about 100m away from where the blast occurred and had to be evacuated.
They packed and relocated and at 7pm on Friday he and others who had been evacuated got news from the police.
"They said 'if your house is not one the following numbers you can go back to your house, however there may or may not be habitable'."
Police said there would be no gas for properties in the area but Gin's home would not be affected as it ran on electricity.
The Gin family have decided to stay in their home as further assessments are carried out.
