Authorities say they will assess Christchurch's shattered CBD building by building, and make no apology to business owners for the time it will take.
Many business owners have been voicing anger and frustration at not being able to get into their premises within the central cordon area.
Some are planning a protest at the Civil Defence control centre today to get their message across.
Many buildings within the cordon have been inspected and given a yellow sticker - which allows limited access, but indicates the building needs further evaluation - or the green stick that denotes the building is safe.
But owners are being denied access because of the danger from surrounding buildings.
Yesterday, authorities showed the Herald through an area inside the cordon in a bid to get the message across to business owners - a green sticker doesn't necessarily mean it's safe.
Urban Search and Rescue (Usar) engineer Carl Deveraux pointed out buildings that had been deemed structurally safe, but were unsafe because of others around them.
On one side of Hereford St a three-level building had been inspected and deemed safe. But the danger posed by the crumbling and cracked Kenton Chambers building meant the entire block was inaccessible.
"It's just not safe," he said.
"There is a real mixture of buildings. The one behind me is probably 1970s reinforced concrete frame building ... and very robust, very solid, there's hardly a scratch on it.
"But across the road Kenton Chambers is a multi-storey, unreinforced masonry building ... and it just hasn't performed that well.
"The large diagonal cracks all the way down and especially at the base make that building completely unstable - the reason this whole street's in lockdown at the moment."
Further up on the corner of Manchester and Hereford Sts, a Chinese restaurant remains standing with not even a window broken.
But on the building behind it, a three-storey-high brick wall has come loose and is leaning over the restaurant.
Mr Deveraux said it would be a long time before people were allowed back into some buildings because they were too dangerous.
Usar officers had spent a lot of time deconstructing parts of buildings to make them safer.
Mr Deveraux said officers were not there to carry out demolition, but had pulled down unstable roofs, facades and walls to ensure they did not fall on any staff or block roads needed by emergency services vehicles.
The Usar officers were packing up and heading home, handing the red zone over to Civil Defence for the next phase - building recovery and demolition.
Said Civil Defence controller John Hamilton: "We've done all the urgent work to make buildings as safe as they can, which is the Usar task. Now we're into demolition, but before we get carried away with it we want to give as many businesses as we can the opportunity to access materials."
"But of course there are some buildings that are highly dangerous and the chances of getting anybody into those buildings is pretty well nil.
"We'll take it building by building, almost, to provide safe access for people and it's going to take a long time," said Mr Hamilton.
He said he sympathised with business owners, but was not prepared to rush the process.
"It's critical for Christchurch to be able to get the economy back and running because obviously the CBD isn't going to run for a while.
"It's a tough thing for businesspeople. But I'm not prepared to jeopardise any individual safety."
Accounting firm Allott, Reeves & Co is based in the Civic House building which was largely undamaged.
The building has been yellow-stickered, but because the building next door - music venue The Civic - is extremely unsafe and due to be demolished, no one can get in there.
Director Philip Rawlings said he appreciated why he could not get into his building, but it was still frustrating.
"It's a pretty big mess in there. Being there on the day and being back once since then, you appreciate what it's like in there," he said.
"There's a lot of high rise buildings that have issues with them, so that obviously complicates things for the rest of us."
Mr Rawlings has organised new office space and said he and his staff would never go back to work in the central city.
But he still wanted to know what would be happening to his Manchester St site and said it was extremely hard to get answers.
"They don't communicate with business owners. You have to find out yourself by ringing the various numbers.
"The biggest thing I'm worried about is the communication. We're not asking to go in there, we'd just like things to be a little bit clearer.
"I heard that it could be three or four months before we can get back in there.
"Why can't [Civil Defence] communicate and say 'this is what we're thinking, this is where we're at'?"