Stories of heroism and desperation are emerging from the Wellington hostel fire that has killed at least six people.

Police and emergency services are yet to gain access to the Loafers Lodge hostel, where several people died after a fire started about 12.25am on Tuesday.

At least one man jumped from the burning building to save himself, while firefighters also winched five people to safety from the roof using an aerial truck.

Fire and Emergency NZ deputy national commander Brendan Nally said, "Those people were going to perish except for the intervention of our team".

"The young officers that led that did an absolutely outstanding job. Multiple people are walking around because of that," he said.

"The firefighters that responded did an outstanding job. I'm just so proud of them."

Tala Sili, a fourth-floor resident of Loafers Lodge, told Radio NZ smoke was creeping into his room under the door and when he opened it, the hallway was "dark and black".

"I was on the top floor and I couldn't go through the hallway because there was just too much smoke so I jumped out the window," he said.

"It was really scary but I knew I had to jump out the window or just burn."

Mr Sili was treated for a sprained ankle after landing on a roof adjoining the property, two storeys lower.

The hostel's website describes it as "Wellington's most convenient and affordable accommodation option".

It is used for both short-stay travellers, long-term residents and other vulnerable Kiwis in need of shelter.

It has sparingly been used as a home for emergency tenants, and for 501 deportees from Australia.

The identities of the victims are not yet known.

Residents told local media fire alarms did not sound in the building, which was not equipped with sprinklers.

"I heard a voice coming down the passageway saying 'evacuate, evacuate, the place is on fire'," Chris Fincham told Radio NZ.

"I sat there for about five minutes and then I put my shoes on, got my wallet together, and I thought maybe I should leave."

Second-floor resident Miimetua Cameron told TVNZ residents were "like a big family", and she only escaped when she heard someone screaming from outside.

"(They) told me to get out cause he couldn't see me on the road with everybody else," she said.

Local MP Grant Robertson said he had visited the emergency shelter, where local agencies were providing support.

"There are some extremely traumatised people there," he said.

"Many people there have lost absolutely everything they've had.

"The number one priority is to give those people a warm dry bed to sleep in tonight ... it's about clothes, it's about kai (food) and getting them a bed."

Mayor Tory Whanau said about 50 people had been displaced by the fire, with support workers relocating around 20 by 5pm.

"They've been given access to things like blankets, food, showers and made comfortable," she said.

Wellington City Council has contributed $50,000 to City Mission relief fund, with locals asked to give if they can.