Deputy Rural Fire Officer Jamie Cowan is leading the investigation and said this was a good time for people to remember the importance of fire safety and the rules around open fires.
"Otago is currently in a restricted fire season, which means any outdoor fire in the region needs a permit from ORFA.
"This is incredibly important from a safety perspective, if anyone had been camped in the Rat Point area when the fire spread the consequences could have been much worse.
"Fires like this move at tremendous speed once they catch and are incredibly dangerous."
He asked anyone with potentially useful information to get in touch while it was still fresh in their minds.
This morning Queenstown Lakes District Council said ground patrols monitored the Rat Pt fire overnight and helicopters were on standby.
Rain helped and there have been no flare-ups since last night.
Power company crews worked overnight and restored power to Glenorchy about midnight, much earlier than anticipated.
Otago Rural Fire Authority incident controller Phil Marsh said that although the fire was controlled, fire crews had a lot of work to do before it would be considered out.
It was expected to take three to five days to fully extinguish the fire.
"They will be working hard over the next few days to make sure it's safe.
"The crews involved yesterday did an outstanding job and it's a credit to their skill and professionalism that we've had over 50 people working alongside eight helicopters in a very demanding environment with no incidents or injuries."