Gardai are investigating two separate fires, in counties Mayo and Laois.
A forensic examination will be carried out today - at the scene of a blaze at a machinery plant in Ballinrobe, which took over four hours to extinguish last night.
Meanwhile, Main Street in Ballinakill, Co Laois is closed this morning due to a fire at a derelict building.
Fire crews are still at the scene.
No-injuries were reported in either incident.
