Northern Territory Fire and Rescue Services are investigating a fire that destroyed a house in Sadadeen overnight.

Two fire crews responded to a report of a structure fire on Spearwood Road just before 9pm.

A smoke alarm alerted the occupants, one adult and five children and they managed to evacuate and call triple zero before the fire fully engulfed the home.

The area has been cordoned off and declared a crime scene until Fire Investigators can determine the circumstances surrounding the cause of the blaze.

No other properties or injuries have been reported as a result of the fire.