Strong winds which have fanned throughout the afternoon and evening has led to the fire creating its own extreme fire behaviour, the statement said.
"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 said.
"Six helicopters have been working on the fire throughout the afternoon and evening and we are expecting another six tomorrow.
"Fire and Emergency have also requested two fixed-wing planes for tomorrow as well."
Overnight, 12 firefighting crews will be on site to monitor and manage any spot fires in the grasslands and protect any structures.
The statement said no one has been reported to have sustained any injuries and the wind is expected to ease before the morning with a northerly change.
This is what estimated 120 hectares fire looks like. We and whanau are safe, but people closer to the fire are being evacuated. #tasmanfirepic.twitter.com/2EskvdpxNp
Tasman Mayor Richard Kempthorne said the fire was devastating for the local community.
"It's a wicked fire and we've got exceptionally dry forestry and there's been a strong wind blowing which has just whipped it through," he said.
"It's covered quite a lot of ground and it's really a very unpleasant fire, so it's really quite impactful."
Residents in Pigeon Valley, Eves Valley, Eves Valley Saw Mill and Golden Hills Rd in Appleby have all been told to evacuate.
As of 10.40pm, FENZ were advising those on Melling Rd to evacuate immediately.
Redwood Valley residents were told by emergency services to be prepared to evacuate at a moment's notice. The exact numberforced to evacuate was not known, but Kempthorne said it could affectmore than 100 properties.
He said the fire was difficult to fight and he was pleased with the efforts of emergency services.
Police are continuing to assist Fire and Emergency New Zealand and asks people to avoid the area at all times while emergency services work to manage the incident.
Stephen Cox said the Nelson area hasn't seen rain in over a month and with dry conditions the wind is helping to fuel the fire.
Cox said he first heard sirens shortly after 2pm and only a small plume of smoke could be seen. Nowthere is a "huge ball of smoke".
"[It has been burning] at least two and a half hours ... there was only a small amount of smoke but since then we've had multiple fire engines, multiple police vehicles all hurtling out there," he said.
Police are urging those nearby to evacuate. Photo / Stephen Cox
"We haven't had rain here for weeks and weeks and there's quite a strong southwesterly wind helping the blaze."
"There's just a huge ball of smoke and [water] tankers going out there and fire engines going out there."
A Civil Defence centre has been opened at St Johns Anglican church, Edwards St, Wakefield to help those evacuated.
Three helicopters have been tasked to tackle the blaze, along with fire crews from throughout the area. Photo / Nelson Weekly.
A spokesman for the Tasman District Council asks people who have been evacuated to register at the centre to ensure their whereabouts is known regardless if they choose to stay at the centre or not.
Smoke from the #Nelson area fire is evident on the Himawari visible satellite pictures. Follow the advice of @FireEmergencyNZ and local emergency officials. The sight and/or smell of smoke may occur in or north of the Wellington area this evening and tonight.
The large blaze was ignited by a passing train around 3.30pm, a Fire and Emergency New Zealand spokesman said.
Earlier today firefighters were called to a blaze that broke out in the Whakarewarewa Forest in Rotorua.
The fire was about 20m by 30m in size and just 100m from a primary school.
FENZ fire risk areas
Extreme risk: Northland, Coromandel, Nelson, Marlborough. A total fire ban is in place for these areas.
Fire restrictions: Auckland, Hawke's Bay, Bay of Plenty, Central North Island, Wairarapa, Southland/Otago and, as of January 29, North Christchurch.
If you are in one of these areas and thinking about lighting a fire, go to www.checkitsalright.nz to check your fire type and, if needed, apply for a fire permit.
