Residents would not have to move out during the clean-up but would be squeezed up into one of the home's two wings while the other was being cleaned. Other services in the same building, including a GP clinic, were not affected, Mr Tuohy said.
Kaeo fire chief Lindsay Murray said the blaze started about 2.55am in a hallway switchboard. .
"I grabbed the CO2 extinguisher and gave it a bit of a squirt ... There was one person still inside so I sent in a firefighter in breathing apparatus to get him out."
The smoke alarms went off but the heat was not enough to activate the building's sprinklers.
"The nurses did a great job getting the residents out, and we did a great job putting the fire out - but we do need more volunteers," Mr Murray said.
Power was restored to most of the building yesterday morning.
Acting chief executive Patricia Howitt, who has been job-sharing the role since the departure of Garry Ware last month, said damage was limited to the corridor floor and a section of wall.
The Kerikeri Fire Brigade also attended, using their thermal camera to check for heat in the walls and ceiling and an extractor fan to clear the smoke.