Fire and Rescue NSW Gunnedah attended the scene in Conadilly Street at about 3am and found the house fully alight.

Deputy captain Andrew Johns said the occupants, an elderly couple, safely escaped the building with the help of a bystander.

Mr Johns said it was "a very intense fire" and the crew focused on protecting the neighbouring properties, a home and a hotel, then turned their attention to extinguishing the fire.

The hotel next door was evacuated and Fire and Rescue Boggabri, Gunnedah Rural Fire Service, Gunnedah police and Ambulance NSW attended the scene.

A carport was destroyed and two cars down the side of the house were "both completely destroyed".

The crews managed to save the garage at the back and were on the ground until 7.45am.

Gunnedah police and firefighters returned to the scene later this morning.

"We got called back by police for what they call a reignition, which is pretty common with a structure fire," Mr Johns said.

The firefighter said a crime scene investigator also visited the property to determine the cause of the blaze.

"Obviously, the couple are devastated with the loss of the house but the main thing is that everyone is okay," Mr Johns said.

"You can replace the house but you can't replace the people."