Police investigating a fire in Glenholme made an arrest at the scene, but say it is unrelated to the cause of the blaze.
The fire at a two-unit flat in Kotare St broke out shortly after 6am on Sunday and left one occupant, a man in his 20s, in Rotorua Hospital in a serious condition suffering from smoke inhalation and a cut to his arm.
The other occupants of the unit where the fire broke out were able to escape unharmed, along with the elderly couple living in the adjoining unit.
Rotorua police Inspector Ed van den Broek said an arrest was made at the property where the fire occurred, but it was unrelated to the blaze.
The person had been arrested for a historic offence and will soon appear in court for that offence, he said.