Crews arrived at the first blaze, which destroyed a house in Allandale Street, Kearsley in the Hunter Valley, just after 3am Saturday morning.

FRNSW say flames had taken hold in the roof upon arrival and firefighters worked quickly to extinguish the blaze, protecting a nearby property.

Initial reports suggested people were still inside the burning house but FRNSW confirmed it was unoccupied.

"Investigations are continuing but it looks like an electrical short in the fridge motor is the likely cause of the fire," FRNSW acting superintendent Mathew Sigmund said.

"It's a reminder for people to check their smoke alarms because we know smoke alarms save lives."

The second fire, which Mr Sigmund said was likely started by a lithium battery overheating, started in the property's garage before setting fire to the adjoining house in the Port Stephens neighbourhood of Corlette.

FRNSW crews from Salamander Bay Fire Station were called to the Bottlenose Street property just before 3:30am, to find residents had escaped the burning home.

They say the owner discovered the garage alight after being woken by a "large bang".

The garage contained a large amount of flammable material and was well alight with flames visible through the roof when crews arrived.

"The flames and extreme heat, generated by those contents, spread to the adjoining house," FRNSW said.

"Crews from FRNSW contained the blaze but the house was severely damaged."

Mathew Sigmund said he wants to remind people who may find themselves facing a housefire to "get out and stay out" and to call triple zero as soon as possible.

IN THE NEWS:

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: