For many residents of Christchurch, it was one shake too many.

Thousands of the city's 350,000 inhabitants have left in droves, flying, driving, even walking away, with no plans to return any time soon.

More than 50,000 have left from the airport alone in the days since the earthquake. Christchurch airport chief executive Jim Boult said as many as 32,000 people left over Wednesday, Thursday and Friday.

"Over the weekend, it quietened down a little more to be about 8000 or 9000 [a day]. "Normally we only see about 5000 a day."

Among those leaving is Aaron Waine who lost his mum Susan Chuter when the Canterbury Television building (CTV) collapsed.

"We can't stay here with this constant horrible reminder of what's happened here and what we've lost," Mr Waine said.

Australian Gloria Cotton, 84, said: "We can't live like this, with the constant shaking." She had lived in New Zealand's second largest city since meeting her Kiwi husband there 15 years ago.

"My heart is here, and I feel so heartbroken at the thought of leaving.

"This is no place to live any more."

In the quake-hit suburbs, the exodus is well under way.

An estimated 50 per cent of homes lie empty on the stretch of hillside coast from Mt Pleasant to Sumner. Locals cite ruined homes, a need to protect family and a lack of official support as the reasons for leaving.

In Redcliff, the Herald witnessed residents going through unmanned official cordons to enter cliff-top homes from which they had been evacuated days before.

They said they had taken advantage of the disappearance of soldiers who had been manning the cordons to salvage valuables, acknowledging the houses might collapse at any moment.

Teacher Michael Matulewicz was salvaging his mother-in-law's art collection from one of the banned areas. "We're not really meant to be down here," he said, loading a trailer. "It may be about to collapse."

In Mt Pleasant, residents raced to empty belongings from ruined houses before they were "red stickered" - the Earthquake Commission's official ban barring people from their homes which sees a red notice fixed to the front door.

An informal cellphone network quickly developed when Earthquake Commission staff appeared in the area yesterday morning. By phone call and text message, resident warned resident of the approach of officials, spurring an even hastier emptying of houses.

Painter and pastor Danel Rea had emptied his home contents on to the lawn to sort it for storage in Rolleston. He, wife Marie and their 10-year-old son had lived there for a year.

"We're getting all our stuff out. We just don't know when it's going to go."

Father-in-law Geof Pannett, 66, said: "This street is knackered."

At nearby Mt Pleasant Primary, the emptying out of the suburb was plain by the empty tents on the school field.

Almost 40 tents had been put up by locals on Tuesday and Wednesday after their houses became too badly damaged to live in.

The tents were still there - but only three remained occupied yesterday.

A few bays along, Sumner Supervalue Supermarket owners Chris and Annie Milne were advertising for staff yesterday. Mrs Milne said some residents had left Christchurch to live in holiday homes while others had left to enrol teenage children in high schools in other towns.

"We had to put the job sign out because a lot of our staff can't work," she said.

The emptying was "serious", Mr Milne said.

"A major part of our client base have left town and may never return."

Deputy chief fire officer Daryl Sayer said army units were carrying out foot patrols at night.

"We're running on adrenaline. The guys are in awe of the support they are getting from other brigades, agencies and the public."

The Canterbury Chamber of Commerce fears many businesses will have the same response as individuals and families, relocating en masse to other New Zealand cities so they can keep going. Chief executive Peter Townsend said there were companies with 1000 employees ready to return to work, but a lack of basic utilities, an office and, in some cases, demand for their services, was stopping them.