The man arrested for arson over the fatal Loafers Lodge fire last month now also faces murder charges.
Wellington Police on Thursday filed five murder charges in relation to the fire in Wellington's Newtown.
On May 16, a large blaze broke out at the hostel in Newtown where over 90 people resided, killing five people, injuring 20 and leaving dozens effectively homeless and without any possessions.
A homicide investigation was sparked and a couple of days later a 48-year-old man was arrested. He is currently remanded in custody on two counts of arson but is now also facing additional murder charges. The man has interim name suppression.
Police said the victims' families have been advised of the new charges.
"Our thoughts are with them and we are continuing to ensure they are supported through this process," a police spokesperson said.
Police have finished their extensive scene examination of the hostel and on Thursday handed the scene at Loafers over to Fire and Emergency (FENZ). Once FENZ has completed their work, the site will then be handed to Wellington City Council and the building owner.
Once the building is returned to the owner, they plan to facilitate any return of personal property from the building in cases where rooms and/or items have not been destroyed or contaminated by fire, police said. There is no current timeline for this, and would require the owner to do their own due diligence in terms of safety.
"I want to thank our partner agencies in this investigation, including FENZ and Council, for their co-operation and assistance during this incredibly difficult and detailed investigation," Acting Wellington District Commander Inspector Dion Bennett said in a statement.
"Also our sincere thanks go to local residents and businesses who have been impacted since the fire occurred.
"I also want to acknowledge Police's investigation team, who have been working tirelessly and methodically to bring about today's result.
"We are thankful to Te Ati Awa for their guidance and support."
A dawn karakia will take place on Friday for the staff involved in this operation.
"Finally, Police would like to acknowledge the residents of Wellington who have been affected by this tragedy, and we hope that today's upgraded charges will be welcomed," Insp Bennett said.