Safe in their new rented house with a view of Rangitoto Island, the Haybittle family from Christchurch still feel guilty every time a new aftershock hits their friends back home.

"It kind of feels like we've ditched them all," says Patrick, 12.

Three months after moving into their new home in Milford on Auckland's North Shore, mother Kelly Haybittle is still feeling fragile.

"Every time there is a shake down there now, there is the guilt that we ran away," she says. "But I sit and look at the water, and it's calming."

The Haybittles are among a lucky trickle of Cantabrians who have been able to get out after the string of earthquakes that has devastated much of the city since last September.

Data from postal redirections, school enrolments and other sources suggest that so far between about 8500 and 13,000 people, or 2 to 3 per cent of the population of Christchurch and adjoining Waimakariri and Selwyn districts, have left Canterbury.

More seem bound to follow in the wake of Thursday's announcement that 5000 homes along the Avon River will never be rebuilt, with a further 9000 still in an "orange zone" and others, damaged again in the June 13 magnitude 6.3 quake, that still have to be assessed.

The immediate crisis of February, when the air force airlifted out elderly and disabled people from collapsed rest homes and Air New Zealand laid on $50 flights from Christchurch to anywhere in the country, is over. Many residents have hung on, staying with friends while they wait to find out what is happening to their homes or surviving on three- or six-month bank mortgage holidays that are starting to run out.

But it has been clear for some time that this was only the beginning - that rebuilding is going to take years, and that life is going to be tough for a long time. And the aftershocks show no sign of diminishing.

"It's a long, slow exodus," says marketing consultant Carren Richardson, whose work prospects in Christchurch evaporated on February 22. She brought her two children to Auckland within days, but her husband commuted between them and his Christchurch job for three months until he found a new job in Auckland.

Those who have got out so far, like the Haybittles, are mostly those who have been able to find new jobs, could afford to move financially and have not had to leave elderly parents behind.

Brian Haybittle was born in Canada and most of his relatives are overseas; Kelly's are all "at this end of the country", and the family lived in Pukekohe before moving to Christchurch five years ago.

Brian is an Air New Zealand pilot. He was able to transfer his job back to Auckland and rented out the family's damaged but still liveable Christchurch home to a fellow pilot.

Even for a pilot, Milford rents are a stretch. Kelly has had to get a part-time job at Albany's Burnsco Marine on top of an internet-based beacon-rental business which she has kept running from home.

Children Carmen, 10, and Patrick are both keen sailors and windsurfers and already had sailing friends on the North Shore.

Brian argues that the family is actually helping Christchurch by leaving, reducing the strain on damaged sewers and renting their house to a family whose own home had crumbled.

And every time Kelly feels guilty about leaving, she reminds herself, they did the right thing. "We just felt, we can go, we will go,"' she says.

There no definitive figures yet on how many people have left. NZ Post says 9050 Cantabrians arranged mail redirections between February 22 and May 20, compared with 3496 in the same period last year. But only 1781 redirections were to places outside Canterbury, representing 1.1 per cent of the households in Christchurch, Waimakariri and Selwyn. About 42 per cent of these (749) were to elsewhere in the South Island and 942 to the North Island, including 391 to Auckland. Ninety went overseas.

School enrolment data point to higher numbers. One in every nine schoolchildren from Christchurch, Waimakariri and Selwyn (8304 out of 76,143) re-enrolled in new schools outside those districts after February 22, and 2200 (2.9 per cent) were still enrolled outside Canterbury this week.

Auckland Primary Principals Association president Terry Hewetson says all seven who came to his school, Glen Eden Intermediate, have gone home. Six stayed with relatives and in another case the parents came too, before returning to Christchurch six weeks later.

"When they came to see me they were almost in tears. You actually were counselling the parents more than the children," he says.

John Wilkinson of Mt Roskill Grammar says the two boys and a girl who turned up at his school are still there, staying with relatives.

In other cases, whole families have moved. Papatoetoe High School Year 12 student Cynthia Nath, whose family came from Fiji four years ago, says her parents both lost their jobs in Christchurch and found new jobs within two weeks of moving to Auckland. They stayed with cousins at first but have now rented their own home.

Year 11 student Nishal Chand, also at Papatoetoe, says his family stayed in a motor lodge in Timaru for two weeks before moving north to stay with his uncle. They have found their own place to rent this week but his parents are still looking for work.

Around 3000 mobile young tertiary students have also left and may not show up in either the NZ Post or school data. A sixth of all New Zealand's fee-paying international students were in Canterbury last year (1649 out of 9661). Some died on February 22 and it seems likely that almost all the rest have left or will leave soon.

NZ Language Centres, which had 13 fulltime staff in the condemned DTZ Building in central Christchurch, moved four staff and about 50 students to its Auckland school. Canterbury University transferred about 300 students for the first half of this year to Adelaide (167), Auckland (94), Oxford (43) and other universities.

In theory they are due to return for the second half-year starting on July 11. But marketing consultant Charlotte Tait, whose sister is a Canterbury student, says every new earthquake drives more of her sister's friends to apply to other universities.

"People are going back but they are trying to get transferred again," she says.

University communications manager Jeanette Colman says the university expects to be 1100 domestic and 450 international students below budget for 2011. That's 10 per cent of its roll of 15,500.

Young workers such as Geoff Thompson, 25, who was finance manager for a courier company, have also gone. He found a new job at Westpac in Auckland because his home town is now "a pretty depressing place to be socially".

"After the February quake, socially, you could barely get a beer," he says. "A number of my other mates have left town. It's becoming more and more of a ghost town."

Other people who were not tied to Christchurch by their jobs have moved out. The Ministry of Social Development says 2600 (4 per cent) of the city's 68,000 beneficiaries and superannuitants have left town since February 22.

Housing NZ says 538 (8.8 per cent) of its 6123 Christchurch tenants have left their homes since March 1. It does not know how many left because of the earthquakes but 134 (2.2 per cent) applied for state houses elsewhere.

Housing Minister Phil Heatley says planned sales of state houses remain frozen nationwide while they're are still needed for people from Christchurch. An intake of United Nations refugees due in March was cancelled and numbers coming in since then have been reduced to ease the housing pressure.

Canterbury District Health Board moved 309 people from damaged rest homes to other regions in February and 246 were still away on May 31, including 86 in Nelson/Marlborough, 64 in Otago/Southland, 35 in Auckland and 24 in Wellington.

Finally, Statistics NZ reported this week that 2655 Christchurch residents left the country for at least a year in the three months to May 31, 1224 more than in the same period last year. Numbers arriving into Christchurch from overseas dropped by 400.

This means Christchurch, Waimakariri and Selwyn have lost probably at least 8500 people (2 per cent of their population) so far: 4577 who have redirected their mail (1781 households times the average of 2.57 people per household); perhaps 1100 children who have gone to stay with relatives or one parent while the other parent stayed in Christchurch (assuming the other 1100 children who have enrolled elsewhere are already counted in the postal redirections); 1550 Canterbury University students; perhaps 1000 other international students; and 246 frail elderly.

This assumes that the net loss overseas was largely accounted for by Canterbury University's loss of 450 international students, the 1000 other international students and the 90 households who redirected their mail overseas.

At worst, allowing for young people and others who may have left without notifying NZ Post, the net loss could be as high as about 13,000 - 3 per cent of the population.

Almost certainly this is just the start. Cone Groosen, who came from South Africa with her husband and two children five years ago, says she and her husband have found new jobs in Auckland because their Christchurch jobs were looking shaky.

"Everyone that we know really wants to move away," she says.

Charlotte Tait's parents and other relatives are still in Christchurch but every time she rings them "you slowly hear it getting worse and worse".

"It's just too stressful. It's no way to live," she says.

With 5000 houses condemned already and more to come, quite apart from shaky jobs and the even shakier ground, at least a further 5000 households, or another 13,000 people, may move out over the next few months and years.

This is, of course, a gross figure. Canterbury Employers' Chamber of Commerce chief executive Peter Townsend believes it will be offset by an influx of perhaps 20,000 construction workers and their families in the next few years.

Fletcher Building has already run full-page advertisements in the Herald seeking carpenters, engineers and others to "do good in our garden city", offering "five-plus years secure work" with "skifields, fishing, forests and beaches nearby".

The strain on the rest of the country may be manageable, even for neighbouring regions. The 105 households who have had mail redirected to Marlborough represent only 0.6 per cent of Marlborough's 17,000 households.

The 391 who have had mail redirected to Auckland are less than 0.1 per cent of Auckland's households - far less than the normal intake of new immigrants.

And for the families concerned, moving may not be as traumatic as what they have already gone through.

"We are tough. The earthquake has made us even tougher," says Cone Groonen.

The Haybittles have been overwhelmed with their friendly welcome on the North Shore, where half the Murrays Bay Yacht Club turned up unexpectedly to move their furniture into their new home.

"It just goes to prove we are all Kiwis," Brian Haybittle says. "We are not Cantabrians. We are not Aucklanders. We are Kiwis."

Where have they gone?
9050 Christchurch households changed their postal address between February 22 and May 20 this year.

3496 moved in the same period last year.