The deadly risks of house fires have been highlighted for a Masterton family after two young children fled a blaze that had erupted in their sleep-out.

The children, aged about 7 years old, were gaming in the two-room sleep-out on Tuesday afternoon when they saw smoke and ran to their grandparents' house on the Totara St property to alert fire services

Masterton Fire Service officer Mike Cornford said it was a "wake-up call" for young families to understand the importance of having smoke alarms in detached buildings "because in this instance there were no smoke alarms in the building at all, and at the time there were young children using it as a games room".

The fire was well alight when firefighters arrived and the sleep-out was extensively damaged, he said.


"There were a couple of children playing on a game box in there and obviously the owners are a little upset at the moment so we're being a bit mindful about what we do."

Three fire crews, Wellington fire investigation, police and Powerco attended the blaze at about 5pm, and family confirmed no one was hurt.

Mr Cornford said the cause of the fire had not been determined but initial investigations indicated it "could have been electrical of some description".