Insurance and land-zoning concerns are affecting the mental health of Cantabrians trying to recover from the earthquakes, a psychologist says.
Ron Chambers, of the Canterbury District Health Board, said there were a few "hiccups" in people's reactions to the quakes that broke from the usual pattern for disaster response.
"The difficulty and the difference here is that we've been faced with many thousands of aftershocks which have complicated that recovery process and ... we've had to deal with [issues] around the land zoning and ... insurance,'' he said.
"The unclarity around a whole lot of things like that really have had an ongoing impact on people's stress levels and resilience and ability to move forward."
Chambers told the Australasian Natural Hazards Management Conference that Cantabrians' response to the quakes otherwise followed what was expected after disasters.
A "honeymoon period" of community cohesion came in the days and weeks after the September 2010 and February 2011 quakes, he said, as shown by groups like the Farmy Army and the Student Volunteer Army.
"Then over time, as the reality sinks in, there's a period of disillusionment often that's talked about ... where people's coping ability drops off, their stress levels go up and things bottom out,'' he said.
"Then ... people start to progress, work through the issues, move into the period of new normal and develop a pathway forward."
Most people could mentally recover on their own, Chambers said, but about 15 per cent needed more help.
"There is a group of people ... who experience much greater difficulties and post-traumatic kind of symptoms post-quakes,'' he said.
"Then there is an even smaller group of people who are perhaps more vulnerable with a pre-existing [condition before] the quakes or who develop more complex post-traumatic symptoms, depending on what happened to them in the quake."
Most of the 15 per cent could through primary health services, such as a GP visit or counselling, but the smallest group needed specialist mental health services to recover, he said.
Chch quakes 'best-case scenario'
The Canterbury earthquakes are the "best-case scenario" for how such a disaster plays out in a coastal New Zealand city, a scientist says.
University of Canterbury coastal scientist Deirdre Hart earlier told the conference that Christchurch's geography made it better placed than other New Zealand cities to cope with a major quake.
"At least in Christchurch we had parts of the city that were not coastal. We had inland parts. I'd suggest it is New Zealand's best-case scenario,'' she said.
Wellington was especially vulnerable, she said."If what we've observed here happens to other cities like Auckland, Wellington or Dunedin, the impact would be a lot greater because with the coasts and the rivers, there's a lot less space between them and the city."
"I think the waterfront and the CBD, the reclaimed areas, are very much at risk,'' she said.
"Wellington is incredibly vulnerable in terms of its lifelines. [The Eastbourne] road would crack and fall into the sea. The Hutt Hospital would be cut off.
"The emergency response people already have problems with in a bad storm in Wellington. Add that to when the roads are falling into the sea and crumbling buildings having bits falling off ... I think I'll stay here."
Hart told the conference that coastal and river impacts from quakes needed equal standing with seismic and engineering factors.
About 6500 years ago, Christchurch's coastline was much further west, cutting through Riccarton to the base of the Port Hills, and much of the city was built on ancient sea deposits of silt and sand.
As a result, coastal and riverside areas had extremely vulnerable infrastructure, Hart said.
"When you put infrastructure into coastal and river areas, it's harder to put down a nice, neat grid network,'' she said.
"By putting down roads with pipes and holes underneath and having this inbuilt infrastructure in the deposits, you're magnifying the hazards.
''A lot of the liquefaction that we've seen coming up through roading systems, the recent rainfall, the potholing we've seen, is a product of cracks that appeared in pipes during the earthquakes."
The conference will run until Friday.