Cordons were in place for a time on Sunday morning while officers carried out a scene examination.
The cordon had lifted just before 9am, although a ladder remained leaning on the awning outside the complex.
One resident of the apartment block said he could hear loud noises coming from one of the rooms before there was a loud bang, followed by screams.
Another resident told the Herald it was "chaos" on the street outside shortly after.
"There were police cars everywhere, the street was full."
Four police officers were seen at the apartment block on Sunday afternoon.
One was taking pictures of the building from the opposite side of the road while another left the building carrying two brown paper bags and a box of gloves after talking to reception staff.
One resident of the apartment block, who didn't want to be named, said they heard loud noises and what sounded like a woman screaming just after 3.30am.
Emergency services were on the street shortly afterwards.
In a statement to Stuff, Airbnb's head of public policy for New Zealand and Australia Derek Nolan said the company was devastated to learn of the incident.
"We are shocked and saddened by this tragic incident and we are fully committed to supporting police in their investigations.
"The safety of our community is one of our top priorities and at the very centre of everything we do - and we are devastated to hear of incidents such as these, regardless of how rarely they occur."
The manager of The Liquor Spot, one store down from the suites, said he arrived at midday to find at least 10 police officers on Gore St, coming in and out of the building.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
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• Whatsup: 0800 942 8787 (Mon-Fri 1pm to 10pm. Sat-Sun 3pm-10pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• Samaritans 0800 726 666
• If it is an emergency and you feel like you or someone else is at risk, call 111.