Firefighters battling the blazes ravaging the Tasman district south of Nelson City expect to face another 48 hours of "very hard firefighting" after the fire area expanded overnight.
It grew to 2000ha last night, from 1600ha.
John Sutton, Fire and Emergency NZ incident controller, said it was a challenging afternoon due to wind yesterday with favourable conditions - mainly low humidity - for burning overnight.
The fire was active overnight but at a slightly lower rate of spread, he said, speaking, with other officials, at a Civil Defence public update on the fire situation this morning.
He could report no further structures were lost after that one shed late last night.
"There has been some enormously good work done by our structure protection crews to prevent others burning, and that's actually what we had last night with bulldozers and appliances we managed to save several buildings."
Firefighting teams were optimistic they could defend the southwest corner of the fire zone, he said.
Unfortunately that had affected some of the work Civil Defence was doing in the effort to get people back into homes in Redwood Valley.
"We can't get our own personnel into that to make a risk assessment," Sutton said.
"This morning for us is absolutely crucial.
"We are really trying hard to harden up our protective areas."
The southeastern sector of the fire zone, near Wakefield, "is the immediate risk" this morning.
Sutton said numerous heavy tankers were carting in water.
"Water supplies are holding up - it's not an ideal situation," he said.
They were using private reservoirs, dams and swimming pools, he said.
He believed there would need to be "another 48 hours of very hard firefighting" before the fire could be described as being under control.
Fatigue was an issue for firefighters, it was arduous work and it was getting hotter, he said.
Inspector Zane Hooper, Acting District Commander of the Tasman police, said 13 cordons were in place.
"If you have no legitimate reason to be in an affected area you should not be there - our priority is to ensure the safety of the community.
"We are working with FENZ on a plan to allow residents restricted access where possible and where it is safe to do so."
Tasman Deputy Mayor Tim King said forestry harvesting operations in the top of the South Island had been suspended.
Orchards were also affected and every part of business-as-usual was going to be affected, he said.
A lot of truck drivers had been called in with heavy machinery, away from their own day jobs, he said.
"They are working in industries that are often time critical, in the horticultural industry particularly."
As time passed, flow-on effects would increase, he said.
Firefighters and residents of the fire-stricken zone of Tasman district have been given no hope of help from rain today, but at least the winds are expected to be light.
Isolated showers in the afternoon and early evening are forecast for west of Tasman Bay, but that is 20km from the 1600ha zone in which fires, that exploded in Pigeon Valley near Wakefield on Tuesday, continue to burn.
"I know the fire service would like to hear there's a big band of rain coming over but unfortunately that's not the case," said MetService meteorologist Lisa Murray.
Overnight, some residents of Wakefield were evacuated because of the fire burning near their village in Tasman district.
"There were a few evacuated and a number self-evacuated," Tasman District Council member Dean McNamara, who lives in Wakefield, told the Herald this morning.
However, he said the fire was looking less threatening today.
"It looks pretty good at the moment with no wind and the air crews showing up."
And in another development, the police have announced Wakefield schools,
early childhood centres and kindergartens will be closed today.
Wakefield residents told yesterday to prepare to flee have woken with relief that the fire hasn't come closer to their homes.
Kelli-Anne Eastmond has been climbing a nearby hill to watch the blaze flare up and get doused down by helicopters and firefighters for the last three days.
She was saddened by yesterday's huge flare-up that spread the fire into previously untouched Teapot Valley.
Officials last night feared the fire could leap down into Wakefield and had told the 3000 residents to get ready to evacuate their homes.
But this morning, they were safe.
"I'm blown away with what I can see," Eastmond said this morning.
"It's been hard, knowing that so many people in our district are affected. For me, as a Christian, I have been praying and praying.
"I'm seeing an answer to my prayers and to the prayers of so many people. There are so many churches in our region and throughout the country who are praying for what is happening here and for the winds to be still.
"Seeing the fire brigade, the volunteers in the air and on the ground, you feel for their safety and you pray for their safety as well.
"Yesterday the winds were really really strong and … there was a lot of people sitting here watching their properties in danger and there was not a lot of hope, there was a hopelessness feeling, and quite sad. So today to come up and see what I can see, with what appears not a lot more damage … it's honestly been a miracle. And I will keep praying until this fire is out."