Up to 50 people were last night believed to be trapped as firefighters battled a fire and rescue teams searched the remains of the building on the corner of Cashel and Madras Sts.
Ms Oxnam, who works for Otago Daily Times sister publication Country Courier in the CTV building, had left her second-floor office to eat a salad in the food hall of landmark Christchurch department store Ballantynes when the quake hit.
''There was this huge noise when parts of the ceiling and lights came down ... Fortunately, I was beside a pillar which protected me.''
Staff assisted customers from the store.
Outside, she witnessed a ''devastated central city'', and people walking around dazed and injured.
On her return, she found the CTV building reduced to rubble, and on fire.
''It is just a devastating sight.''
Ms Oxnam said she could find just a few of the dozens of staff who worked in the building, and had grave fears for the safety of others.
Police sent her and other onlookers to nearby Latimer Sq, where a temporary triage centre had been established, and she saw several bodies.
''I didn't want to stick around.''
Allied Press, publisher of the ODT, owns 50% of CTV. Christchurch businessman Murray Wood owns the other 50%.
Allied Press chairman Julian Smith yesterday said the company's priority was the wellbeing of its staff at both CTV and its various newspaper interests throughout Canterbury, and he was distressed by what had happened in Christchurch.
''Our hearts go out to everyone in the city,'' Mr Smith said.
Allied Press director Nick Smith, the chairman of the regional television station, also expressed sorrow yesterday afternoon.
''It appears we have lost some people and our sympathies go to their families and their colleagues,'' he said.
''Currently, we do not have any confirmed details of staff who have survived. We only hope that the numbers we believe unaccounted for will reduce over the next few hours. Our thoughts go out to Christchurch and its people.''
Nick Smith said he was astounded that what appeared to be a substantial modern building had been reduced to rubble.
CTV leased the ground and first floors of the building.
Another worker in the CTV building, Liz Cammock, told One News she was on the fifth floor when the ceiling and building collapsed, and ''I looked out; I saw we were on the road.''
