A state of emergency has been declared in Tasman as the massive fire continues to burn uncontrolled.
Multiple homes have been swept up in the deadly blaze that has consumed a large section near tinder-dry Nelson.
Nelson-Tasman Civil Defence said the fire has spread and at 11pm on Tuesday night had covered 780 hectares of land. It's now believed to have expanded to cover 1870 hectares.
As yet, there have been no reported injuries but 12 Fire and Emergency NZ crews have been working around the clock to bring the large scrub fire, which started in Pigeon Valley, under control.
In Redwood Valley, where the fire spread to overnight, several houses were lost and evacuations were taking place at a moment's notice, according to the Tasman-Marlborough Fire Service.
Sunrise and Sunset Valley were also preparing for evacuation early on Wednesday morning.
Strong winds on Tuesday were "fanning the forest" and creating the "extreme fire behaviour" that consumed such a large area, Civil Defence explains.
"Due to this, crews have not been able to access the forest areas and are instead focusing on controlling the fire when it's spotted onto grassland," it explained in a press release.
Wind was anticipated to ease overnight, and the main task was to manage spot fires in the grasslands and protect buildings.
Six helicopters were working the area on Tuesday, and another six are expected on Wednesday - as well as two fixed wing planes.
Police have been evacuating residents for whom there are safety concerns overnight, and are attempting to contact all residents affected. They are urging those worried about their immediate safety to call 111.
Police say those with concerns about themselves or their property should also evacuate to a Civil Defence centre that's been set up at St John's Anglican Church in Wakefield.
"Even if you are not intending to stay there for the evening, please register to help us make sure everyone is accounted for," police advise.
"All other people are asked to avoid the area at all times while emergency services work to manage this incident."