The Rural Fire Authority says it has control of about 65 percent of the six hundred hectares that is either burned or still burning in Marlborough.
The fire at Onamalutu Valley has been burning since Wednesday.
Incident controller Rob Hands said the fire has a perimeter of about 16 kilometres.
He said fire fighters have made great progress in conditions that can change quickly.
"Indications from the field are now that it's probably getting towards 65 to 70 percent controlled - obviously there are still a couple of hot spots that can move, but we're reasonably confident at this stage."
Mr Hands said none of the firefighters have been injured since the blaze started.
Mayor of the Marlborough district Alistair Sowman earlier said the fire had ignited calls from residents for better communication between people living in the area.
He said residents have told him they want to restart a community association. He said some of these people live in remote areas and they need to link up in case of emergencies.
Yesterday, about 80 residents of Onamalutu valley were told to pack and be ready in case they need to be evacuated.
The cost of fighting the fire has now reached $500,000.
The Marlborough fire, from above. Photo: RNZ / Jason McClelland
Principal rural fire officer Richard McNamara said the cost was high because of the extensive use of aircraft, including helicopters.
"This fire's extensive and there's a lot of heavy machinery use too, there have been three dozers and couple of large diggers and we've got upwards of 16 heavy water tankers.
"So the costs stack up pretty quickly."
Residents said firefighters were doing a remarkable job of protecting their homes from destruction, but said people wanted answers as to what caused the fire.
Richard McNamara and Rich Law, from the Blenheim rural fire force, in front of the incident control point. Photo: Paloma Migone
Onamalutu Valley resident, Robin Adair said there various rumours were circulating about how it started.
"The big question in my mind is how did it start, I don't think they've really scratched the surface on that one."
Fire 'still contained'
The fire's incident controller, Rob Hands, said there were some small flare-ups overnight in waste areas left by forestry companies, but the fire was still contained.
He said all but five aircraft had been stood down, but aviation companies remained on stand-by.
Mr Hands said he was organising thermal camera imaging technology to arrive today to help identify where the fire is smouldering underground, as crews work their way toward to centre of the blaze to extinguish it.
