Civil Defence and Fire Services say there is no indication of the current situation ending as the Nelson-Tasman fire continues to burn.
On the frontline of this devastating fire which has destroyed one home, displaced thousands and drained fire, police and defence force resources from around the country, they're doing the grunt work.
It's not exciting, it's not glamorous and it's certainly not easy.
But on this pine forest block above Teapot Valley, south of Nelson, firefighters are trying to wrest back control of wildfires that have consistently had the upper hand since the alarm was first raised five days ago.
The Herald on Sunday yesterday afternoon travelled behind the cordons to one of the containment lines where firefighters are doing their best to gain control of the fire.
Here, at the smoky, dusty and noisy site they've named Alpha, their efforts - which have protected several nearby homes - are working. And so are they.
Ashton Oliver looks down into a valley where some of the four crews of four firefighters each are working at Alpha, and he knows they're doing it tough.
But they're also doing it real, the deputy principal rural fire officer for Nelson Tasman told the Herald on Sunday.
"It's very hard work. What these guys are doing, this is the real firefighting work. When the flames have gone, that's basically when the grunt work starts - the really unglamorous, hard, dirty work.
Firefighters work to contain the edges of the Tasman bush fires at Teapot Valley near Nelson. Photo / Mark Mitchell
"Those guys are really doing the hard graft when it comes to putting the fire out, and this could take weeks to put out."
Below him, firefighters are dragging hoses down hills, digging dirt and putting out hot spots churned up by bulldozers. Above, four helicopters circle anti-clockwise, scooping water from a nearby pond, dropping it on flare ups and then continuing the circuit to do it all again.
At Alpha site, it's all going to plan.
"It looks quite dramatic but ... we're using fire to put the fire out. We're steering it where we want it, with the helicopters, the guys and the firebreaks we're guiding the fire around to try and burn out some of the unburnt fuel that's still in the fire ground."
The goal of the containment line was for the fire to burn back to the perimeter, so there was no more fuel to burn and - once hot spots were put out - firefighters could turn their vital efforts elsewhere.
Firefighters work to contain the edges of the Tasman bush fires at Teapot Valley near Nelson. Photo / Mark Mitchell
"We'll try to get a 30 metre blackout zone from the containment line back in, so that 30m should be blacked right out. Within the fire it will still be hot, and smoky, but we try to get that 30m from the containment line blacked out all the way around. That's the idea."
As the firefighters at Alpha worked, they were only a small number of those battling the wildfires that have caused so much anguish and disruption around the district - about 150 people, two thirds on the ground, were involved in the firefighting effort yesterday .
As Oliver spoke, a stiff nor-east breeze could be felt. Gusts around 30km/h were recorded yesterday, but higher winds are forecast.
That's why yesterday's graft was so important, he said.
"The wind tomorrow ... it's a concern to us. What we're really trying to do is strengthen those containment lines around it, so if we do have a day where it's going to blow up our containment lines will still hold.
