IAG owns some of this country's biggest insurance brands including State Insurance, NZI, Lumley Insurance and AMI and Johnson also revealed another post-earthquakes threat: "The most scary part of my career was in 2011 when I found out we might not be able to get reinsurance in New Zealand and I'd only arrived in 2010," she said.
But New Zealand was one of the highest insured countries in the world as a percentage of GDP "and we have a legacy to protect and we must leave it in a way that keeps insurance available."
Some ethnic groups showed a lower appetite for insurance than others.
"If you're of European descent, 88 per cent of New Zealanders are likely to have insurance. It goes back to our history. If you are of Asian descent, what's the penetration rate? - 55 per cent if you are living here," she said.
Asian migrants often came from countries where they lived with extended families, where someone was always home.
Some people did not have a natural propensity to buy insurance "and we have to stimulate that", she citing Pasifika people living here with an insurance penetration rate of only 25 per cent.
"We're very proudly saying we are the most highly penetrated insurance marked but break that down by ethnicity and it doesn't show that."
Johnson said insurance affordability provided challenges.
"I'm constantly asked about why premiums changed in 2012 'because it's about those Christchurch people or those Wellington people' thinking there are no hazards in Auckland so we have to try to education people, without panicking a whole community," she said.
She cited the example of people with a second car might decide to save the money by not insuring it "thinking it's only worth $800 but not thinking about what I might hit which might be worth a lot more than $800."
Natalie Jackson, professor of demography at Waikato University's National Institute of Demographic and Economic Analysis, told of places in decline and Johnson said these trends posed problems for the insurance sector.
"If houses are being left, rented out or not maintained, what does that mean for how we insure that property?"
Jackson told the conference of the threats of depopulation and how older people could be forced to walk away from their houses, unable to afford the rates.
"We're now at the cusp of a mementos change where there will be more elderly than children in New Zealand by 2026, the same time as China. Already 15 per cent of the territorial authorities in New Zealand have crossed over," she said of that massive demographic trend which she called a "remarkable shift".
Between 2011 and 2031, growth in 56 territorial authorities (84 per cent of New Zealand) is projected to be in the 65+ age bracket.
Farmers in New Zealand are now much older, aged 35-39 years in 1996 but last year but now mostly in their 50s and 60s, Jackson said, asking "who will buy the farms?"
Another overhead asked: how much will Auckland houses be worth by 2031 and showed far more accumulators (house buyers) aged 25-64 years than decumulators (house sellers) aged 65+ by 2031.
Shamubeel Eaqub, NZIER principal economist, told how all New Zealand population growth had been in rural areas and how in 1901 the rural sector in employed a third of the workforce but now only employed 6 per cent.
Read an Insurance Council report on natural hazards here:
