A fire investigator who sifted through the ashes and charred remains of a garage at the rear of a Whangarei business says the cause of the blaze remains undetermined.
Firefighters based in central Whangarei had only one block to travel when they were called to Norfolk St about 7.40pm on Wednesday.
The crew were able to stop the fire spreading to the house and a neighbouring garage but personal belongings, including family photos, were destroyed.
Jemma Spence, owner of Koy's Traditional Thai Massage, the business based at the property, said she had all her personal possessions in the garage and had been distraught when she noticed the flicker of flames.
Ms Spence said there were three staff members and two customers having a massage when the fire started.