Family members gathered outside the PGG building on Cambridge Tce in central Christchurch are trying to stay hopeful that loved ones trapped inside will make it out alive.
The top three floors of the four-storey building completely collapsed in today's shallow 6.3 earthquake.
There were varying reports as to just how many people were trapped, but those at the scene reported there could be dozens unaccounted for.
Rescuers were using sledge hammers to get into the building and pull people out, as power to the city has been turned off.
A group of five people who were working for Marsh insurance assessors were the first to be freed.
They were trapped together and said they kept morale up by talking to each other.
Press reporter Martin van Beynen said the mood was still hopeful among families gathered outside the building.
''The mood is hopeful but sombre. People are teary eyed and hugging each other.''
David Hume was waiting for news of his wife of two years, Kathryn. He had not had any contact from her since the earthquake.
The financial planner was on the first floor of the building, he was at home and saw the collapsed building on television.
''I drove to the edge of town and ran from there. It's unbelievable how a new building like that can collapse.''
Wally Tower's wife Gwynn also works on the first floor, he has had no communication from her at all.
His son rang him from Australia after seeing the building on television.
Another woman arrived at the scene crying, ''My baby's in there''.
One man, who declined to be named, said his fiancé was trapped inside. The couple were due to marry on Friday.
Scott Wishheart's partner Anna Harris was working on secondment for Perpetual Plus on the first floor. He had not received a text message from her but another person helping at the scene had told him that contact had been made with her.
The army have cordoned off the scene and rescuers have set up three entry points into the building.
Ross Blackler was on the ground floor about to walk upstairs when the building came down.
''I headed for the doorway and the door came down on top of me. I had no choice. I just stayed on the ground and covered my head.''
''I'm so happy to be alive.''
David Sandeman, 71, was one of the first five rescued.
The five were trapped together on the fourth floor.
''We were trapped under furniture, with probably 12 inches of space. We're just so grateful the guys got up there when the building was rocking and rolling and dug us out.''
''I hope someone will buy me a Lotto ticket.''
Jeff McLay, 50, said they all kept reassuring each other they would be OK as they waited to be rescued.
''I didn't think that would ever be me,'' he said. ''It was pretty awful.''
He said about 60 people worked in the building in total.
''It's not good at all,'' he said.
- © Fairfax NZ News