The 115-year-old Wilmot Country Store caught fire in the early hours of yesterday morning, a smoke alarm alerting the owners early enough to allow them to flee their adjoining residence before it, too, was engulfed in flames.

The store was operated by George Coles snr from 1910 to 1921 and is regarded as the original Coles store.

Coles' son, George jnr, went on to found the supermarket chain.

Fire investigator Adrian Adams said the cause of the fire was still undetermined but the investigation would be completed later today.

The damage bill is estimated to be $600,000, but for residents of the North-West town the loss is far greater.

"Being a small community it's a massive blow to them, so they are all gathered around and supporting each other," Mr Adams said.

"This was their general store, post office and bottle shop."

Mr Adams said it took firefighters just 35 minutes to extinguish the fire, but by then it was too late.

"It's pretty well levelled," he said.

"The local crews here did a good job stopping it from spreading to neighbouring houses."

Owners Pauline and Andrew Towning had recently sold the store to a Hobart-based American couple and were looking forward to returning to Queensland to retire.

The new owners were due to take possession at the end of the month.

- CALLA WAHLQUIST