A sow breaking free from her burning pen alerted her owner to the fire catching onto the side of his house.
The fire started in an Ohakune shed about 10pm when the owner put a heater in it to keep the sow and her 12 piglets warm on Sunday night, Ohakune deputy fire chief Luigi Hotter said.
The property is on Soldiers Rd.
"It caught the straw on fire . . . He was alerted when the sow was breaking out of the pen," Mr Hotter said.
The fire had spread from the shed to the end of the house, but the fire brigade was able to stop it spreading any further.
"He was just very lucky that he had been woken to the noise."
Eight piglets were found alive on Sunday night.
"I don't know whether they all got out or whether there was some turned into bacon."