Six bodies were found but not all areas of the building had been searched yet because the roof on the top floor had collapsed, bringing down debris and making the area unsafe, said Bruce Stubbs, the incident controller for Fire and Emergency New Zealand.
Officials said 52 people had made it out of the building alive but they were still trying to account for others, AP reported.
Loafers Lodge resident Tala Sili told news outlet RNZ that he saw smoke pouring through under his door and opened it to find the hallway was pitch-black.
He said he fell onto a roof two floors below.
The hostel has 92 rooms and features billboards on one side. Dark smoke stains extended up the exterior walls on the top story of the building in an industrial area near Wellington Regional Hospital.
Police said the cause of the fire was not known yet but they didn’t believe it had been deliberately lit. Police Inspector Dion Bennett said the plan was to begin a thorough scene investigation Wednesday after fire officials handed building access off to them.