A Quick Ave house was significantly damaged by fire on June 27.
Fire investigators have determined that two house fires in Whanganui last week were not suspicious.
Fire and Emergency Whanganui assistant area commander Jemal Weston said a fire that significantly damaged a Quick Ave house on June 27 was possibly due to sparks from a chimney getting into a roof void.
A fire contained to two rooms and part of a roof in a Putiki Dr house on June 26 may have been caused by ashes removed from a fireplace.
"It's a good reminder that ashes should be placed in a steel bucket as that's the likely cause of that fire," Weston said.
"These two fires show it's a good idea to have working smoke alarms which are an early warning of these types of incidents."