Light rain in Marlborough has not eased fire risk concerns but is providing a break for firefighters still working on the Waikakaho Valley fire near Blenheim, the Fire Service says.
The blaze broke out last week and ripped through about 450ha of pine forest.
Marlborough principal rural fire officer Richard McNamara said the fires were still burning deeply at a number forestry dump sites, but volunteer firefighters had been pulled out and forestry crews had taken over.
He said the scale of the fire was exceptional as were the efforts to contain it.
"All of that military precision, all of that resource and all of the hard work that's gone in by volunteers, heavy earthmoving machinery operators, contractors, pilots, volunteer crews with urban and rural crews, was directed at ensuring families were able to return to their homes," Mr McNamara said.
Deputy principal rural fire officer John Foley said the forest fire underlined the importance of insurance to rural landowners, who were liable for firefighting costs which could run into many thousands and, sometimes millions, of dollars.
The latest estimate of firefighting costs for the Waikakaho Valley fire was about $900,000, excluding the cost of the damage.
Mr Foley said fire investigators were expected to take another week or two to file their report on the source of the fire which began during commercial logging operations.
The light rain which fell in Marlborough yesterday and again today was not enough to douse the fires but good progress was being made, he said. The firefighting effort had been scaled down to six crews today, including a relief crew from the West Coast, along with two 30-tonne diggers and two bulldozers working at the site.
Mr McNamara said control and responsibility for the management of the scene of the fire had been handed back to the forestry management companies, and the focus remained on ensuring the fire did not spread beyond the perimeter.
"My heart goes out to the families affected by this - the forest has burnt and a lot of forest production potential has gone but people have homes to return to."
Fighting the fire from the air with the number of helicopters used was "starting to push the envelope", he said.
"It was like a military operation. When you have 10 aircraft working in heavy smoke in an area with a lot of overhead wires, we were pushing it but it was done professionally. We had an air attack overhead managing the aircraft - he was flying in a smaller aircraft above the "bombing" circuit, managing those drops for best effect and to link with ground crews.
"We also worked closely with heavy machinery contractors for safety and good effect."
The roads were open again but the public should avoid the area as fire vehicles and forestry trucks were still operating. The current total fire ban in force across the Marlborough District would be reviewed within the next two days.