DOC's chief rural fire officer Paul Hondelink said he expected they could be there all weekend but an assessment would be made in the morning.
A weather forecast for cooler weather and snow in parts of the region today could help the situation.
The fire started when a permitted burn, fanned by a northwesterly wind, escaped from Glen Dene Station into the Craig Burn gully, a popular tramping and hunting access route into the Matatiaho Conservation Area.
Station owner Richard Burdon was away but his father, retired farmer Jerry Burdon, was on the scene as soon as he heard.
Mr Burdon said the fire alarm was raised by an employee about 4pm. The employee had also called pilots Toby Wallis of Alpine Helicopters and James Ford of Aspiring Helicopters.
Mr Burdon was upset and anxious as he stood above the gully with firefighters and watched the fire increase in intensity.
Controlled burns were a good land management practice and helped prevent larger vegetation fires in the summer, but he would not want this to happen, he said.
"The worst thing is, it is on DOC land. I was in the garden when I saw the helicopter go over with the bucket... This is one of those unfortunate things that should not happen but do," he said.
The Matatiaho Conservation Area was created when Glen Dene Station was freeholded in tenure review about six years ago.
Mr Burdon said the beech forest had been regenerating for at least 28 years.
He believed the gully had last been burned about 40 or 50 years ago and it would heal and regenerate.
Mr Hondelink arrived soon after Mr Wallis and Mr Ford began battling the blaze.
He said he called in Wanaka Helicopters pilot Simon Spencer-Bower and two machines from Queenstown to help them, although it would make the gully a "bit tight", because the flames were too intense to fight from the ground.
Mr Hondelink said a decision had been made to let the fire burn out as it travelled down the gully towards State Highway 6, while the helicopters were to drop water at the top of the blaze to prevent flames spreading higher into the Mt Burke Creek reserve.
He agreed that decision meant the Craig Burn beech forest would be sacrificed but there was no other option because of the wind direction and intensity.
- Otago Daily Times