UPDATED 4.10pm: The children who died in a house in Ashburton were aged two, three and five.

The children have been named as two year old Telyzshaun George, three year old Teuruaa George, and five year old Pio Raukete.

Canterbury Police have a scene guard in place at the address and that'll remain in place overnight until a scene examination can take place in the morning.

Earlier today a group of people understood to be family members of Cindy George and her three children who died at an Ashburton house, have arrived at the property.

Two hearses have also arrived at the home.

The family members have been escorted inside the Thomson Street property by police. 

Superintendent John Price said police have yet to finish the scene investigation at the house in Tinwald.

Ms George and her three children were apparently gassed by car that was left running in an adjoining garage.

Ms George was found in the hallway, while the children were in the lounge with the television still on.

Superintendent John Price told a press conference it appears the house filled up with fumes when a vehicle was left on in a connecting garage.

"It appears as though, at this stage, that vehicle has been running and it may have been that the gas or carbon monoxide from that vehicle has made its way into the house," he said.

There was no sign of forced entry, and no trauma to the victims. 

Price said it was a very unusual death but an accidental tragedy.

Neighbour Trudi Arras saw the family out only a couple of times, and they were "very new to the area by the sounds of it. Normal, standard everyday people." 

There was initial concern over a smell of gas in the area when emergency services arrived yesterday.

HAZMAT trucks stationed outside the property, and firefighters wore breathing apparatuses.

Police were door-knocking neighbours, asking them about the gas and checking to see whether they were okay.

 Born in the Cook Islands, Ms George moved to Ashburton about five years ago to work.

Ms George's niece Eireene Atingakua has paid tribute to the family on Facebook, saying rest in peace, you left us too early.

Many family and friends are learning about the deaths through social media.