Whanganui senior station officer Aaron Summerhays said the fire was caught early and caused minimal damage.
But he said the outcome could have been worse had it not been for the neighbour's intervention.
"Smoke was showing from inside the house when we arrived and we forced entry to the house and found the occupant still in bed," Summerhays said.
"Unattended cooking caused the fire but there was early detection by the neighbour due to working smoke alarms. There were two working smoke alarms at the property.
"It highlights the importance of not leaving cooking unattended on a stove and of having working smoke alarms."
Forest was checked by ambulance staff at the scene and did not require hospital treatment.
The fire followed a house fire near Waitotara about 7.45am on Wednesday.
Summerhays said the Waverley Volunteer Fire Brigade was first on the scene and they contained the fire to one room of the house on State Highway 3 on the Nukumaru straight.
Patea volunteer firefighters also attended, along with a pump from Whanganui.
The cause of the fire is under investigation by fire safety staff, Summerhays said.
On Wednesday morning Whanganui crews were also called to Bushy Park and Hikurangi Stayplace after alarms were activated. Both were false alarms.
+ Additional reporting by Simon Waters