Central Christchurch is facing financial oblivion, a local business leader says.
Paul Lonsdale, manager of the Central City Business Association, said up to two thirds of the CBD may need to demolished before the rebuild could begin.
"The reality is that the central city could face complete financial collapse and that's going to have a huge effect not just on central [Christchurch] it's going to have a huge effect on New Zealand."
Canterbury Employers' Chamber of Commerce chief executive Peter Townsend said it would be "some months if not years" before business returns to normal in the central city.
"This is a quantum leap worse than the September 4 earthquake," said Townsend.
"The central business district is seriously trashed."
He said it was unclear how many CBD companies would be forced out of business by Tuesday's quake.
"We're doing whatever we can to get Government support so that as many businesses as possible survive.
"This is the most serious crisis confronting New Zealand and the New Zealand business community in the history of the country."
Ballantynes, the almost 160-year-old central Christchurch department store, was considering moving temporarily to a suburb if the CBD remained shut down for a long period of time, according to a media report.
The report said its CBD store had suffered significant damage to fittings and stock, but the building had stood up to the quake "remarkably well".
Russell Sinclair, of the Retailers Association, said losing the department store from central Christchurch would be like a mall losing its "anchor tenant".
"Ballantynes is an icon - it's a flagship of retail in Christchurch," Sinclair said. "Any move by Ballantynes would obviously have a serious impact [on the CBD]."
Sinclair said Christchurch was known for its abundance of shopping malls in its suburban areas.
"Over time there has tended to be a migration away from the central city, not by all [consumers], but some prefer to shop in the malls."
Asked if the earthquake would increase the speed of that migration, Sinclair said: "It could, but maybe this is an opportunity for the central city to reinvent itself as a more appealing retail destination."
Lonsdale said the CBD would need to be rebuilt in the same place where it is located now, and buildings like the Christchurch Cathedral returned to their former glory.
There had been rumours in Christchurch since the quake about the CBD being moved to another area, which he said was a "silly" idea.
But Lonsdale said a bylaw needed to be introduced, ensuring buildings were constructed to withstand any future disaster.
Meanwhile, Townsend said industrial areas on the fringes of the city appeared to have made it through the quake relatively unscathed.
"The main industrial areas of Christchurch have not been very severely impacted and most of them, certainly most of them on the south-western side of the city are able to operate as usual."