Smoke from the fire could be seen from Parkvale about 15km away.
Firefighters were at the scene of the Kairua Rd blaze for four hours overnight.
Three fire crews from Pāpāmoa, Te Puke and Mount Maunganui rushed to the fire scene about 8.15 pm last night, a Fire and Emergency NZ spokesman said.
When crews arrived the house and garage were both "well involved" in flames.
The firefighters got to work to contain and extinguish the blaze, with the last fire truck leaving about 12.30 am today, the spokesperson said.
Another relative of Kairua Rd homeowners said she spotted plumes of smoke while preparing to have dinner about 8pm last night but initially thought it was a rubbish fire.
"But the smoke just got bigger and bigger and because a lot of our family live on this road, I immediately called 111 to ask if anyone had called the fire brigade."
The woman said her husband and their two children then shot down the driveway to have a closer look and found a well-involved fire at a close family member's property
"We didn't know at the time no one was home. I didn't want to go because I was so terrified someone might be inside the house.
"I thought 'oh my god, on no' and it made me feel sick. I was too scared to go and see for myself so I waited at home for news."
The woman said the homeowners in their 50s, who had lived at the property for more than 15 years, were away in Taranaki.
"It's devastating, they have lost everything, including photos and other sentimental possessions and treasures which can never be replaced."
"We will rally as a family to support them but they will need a lot of support going forward for some time," she said.
The woman's daughter said she, her brother and father also heard explosions and popping sounds coming from the garage where motorbikes and other items were stored.
"It made me feel so sad and ill, but there was nothing we could do the house and garage was engulfed with five minutes. But we did manage to rescue a dog from the property."
The cause of the fire was unknown and a fire investigator was looking into it, but it was not believed to be suspicious at this stage, a Fire and Emergency spokesperson said.
