Update: The cause of the fire is under investigation.
Tauranga Senior Station Officer Len Sabin said the investigation was being undertaken by fire service risk safety officer Jon Rewi.
Mr Sabin said there was extensive damage to one end of the ground floor and smoke damage throughout the home.
Smoke described as "thick and choking" blanketed a small cul de sac in Hairini where a house caught fire around 1.40pm yesterday.
A neighbour on Taumata Pl said the smoke coming from the fire was so heavy he could not see the houses across the street.
Max Briggs, who lived across the street, said he saw the smoke and went over to help get the family out.
"I saw the smoke coming out of the windows and it wasn't too bad.
"By the time we got everyone out, maybe three to four minutes, it had turned into a thick and choking smoke," Mr Briggs said.
He only saw smoke but thought there had been flames as he heard the windows smashing.
Another neighbour said she was driving home from work following a fire truck but had no idea they were heading to her street.
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She said she went to her backyard to rescue her dog and could not even see the dog kennel because of the thick smoke. Mr Briggs said the three people in the home at the time got out all right.
"It's devastating for the family.
"There's four generations living in that house, the grandfather, his daughter, her daughter and her daughter's children."
"We [the neighbourhood] have all been here for years, we're all very close."
He said the family would be well taken care of, having whanau in the area to help out and provide somewhere to stay for the time being.
Another neighbour had opened her home to the family and was providing cups of tea in shelter from the rain.
Mr Briggs said the fire chief told him they thought the fire had started in the basement, but did not know how.
He was impressed with how quickly the firefighters arrived to the scene.
Fire northern communications shift manager Jaron Phillips said the house was well involved with fire when the first crews arrived.
"Initial reports were the bottom storey was on fire. There were people in the house at the time but everyone has managed to escape."
He said three crews attended the fire, which had been contained, and the crews were carrying out salvage and ventilation work.