A group supporting Christchurch businesses says many will have to close because of the time it will take to reopen the zone around the quake-damaged Grand Chancellor Hotel.
The entire operation to demolish the 26-storey hotel is expected to take about 10 months, and it will be about six months before the hotel is down to a safe enough level to allow some nearby stores to reopen.
The Canterbury Business Recovery Network, which supports small to medium enterprises, says there were about 100 such businesses in the drop zone.
The network's chairman, Matthew Carpenter, says some have already relocated and those remaining may not be able to hold out, which will make revitalising the CBD a difficult task.
"The fact that some of the major law firms and accounting firms in town have taken 10-year leases on premises outside of town is an indication of the future of Christchruch as we know it.
"There'll be no attraction for people to go into town for their normal day-to-day business. They will switch to shopping in other areas."
Canterbury Earthquake Recovery Authority deconstruction manager Warwick Isaacs says engineers could be on site in less than a week for initial work to get the hotel ready for demolition.
Mr Isaacs says nearby business owners should be able to get in and assess the state of their buildings once the 26-storey hotel is down to about ten storeys.
Since the quake on 22 February, a large area around the 26-storey hotel has been cordoned off due to concerns that it will collapse.
Fletcher Construction, which has won the tender to bring down the building, said on Wednesday that the structure will be dismantled floor by floor.
Explosives will not be used due to to the risk to surrounding buildings.