Strong winds are the "biggest enemy" for firefighters bravely battling the monstrous blaze that has marched towards the township of Wakefield, near Nelson.
Nearly 900 properties were evacuated in the Wakefield area on Friday - one resident described it to the Herald as being akin to a "war-zone" with smoke, helicopters and small planes looming overhead.
The Wai-iti area just south of Wakefield was yesterday warned to prepare to evacuate, meaning hundreds more could have to pack up their belongings, pets and loved ones and join a mass movement that has already displaced about 2500 to 3000 people.
The message from Inspector Zane Hooper, Acting Tasman District Commander, was clear: "Be prepared to evacuate".
There are estimated to be 170 houses in the prepare-to-evacuate zone, affecting about 450 people.
Speaking yesterday, Nelson Tasman Civil Defence incident controller Roger Ball said there was no end to the state of emergency in sight.
"There is no prospect in the immediate future of that declaration ending."
The situation was dynamic and there remained a threat to life and properties, he said.
People with animals in the Wai-iti area might want to consider moving them to the Richmond Showgrounds, he said.
As firefighting efforts persist in the face of a 2100ha blaze that had a 27km perimeter, FENZ was particularly mindful of the south-eastern and north-western areas.
Fire and Emergency New Zealand incident controller John Sutton said the northerly winds were predicted to develop in the afternoon to 40 to 50km/h with gusts higher.
"This is what is really worrying us, as I have said all along the wind is our biggest enemy."
Once the wind exceeded a certain threshold they could not risk putting firefighters in front of the flames, he said.
"We can't see and it's too dangerous."
The 23 helicopters that were action yesterday can only fly in winds of up to 50km/h.
While residents have publicly praised the firefighters on the frontline as their heroes it has still been an anxious and emotional rollercoaster for many.
Diarmuid Brazendale is one Redwood Valley resident who nearly lost his home on Tuesday.
"On Wednesday morning, we were honestly under the impression our house had gone," Brazendale said.
Brazendale was allowed to visit his property under escort to check on animals later that day.
The trees and outbuildings on his property were destroyed by the fire, leaving just scorched earth.
"Our house is surrounded with black," Brazendale said.
Firefighters had stood outside the house and kept the flames away, he said.
To have no land was upsetting, but they were so appreciative to the firefighters to have a house, he said.
"My 12-year-old girl was evacuated in a hurry and that's hard as a dad to see your kid frightened.
"You want to protect them."
But they were safe, which was the most important thing.