Home-owner numbers are sinking as property prices rise, and Auckland is more than twice as badly affected as the rest of New Zealand.

In the year to March, the number of people who owned their own homes fell 12 per cent throughout New Zealand - and 26 per cent in Auckland.

Research done by ACNielsen for Wizard Home Loans shows the number of homeowners fell from 1.44 million people in March last year to 1.27 million by March this year.

Previously, half the population aged over 15 owned or lived in their own houses. Now, it is 44 per cent, the survey showed.

Wizard's national director, John Grant, said the Nielsen survey showed New Zealand was divided into "property haves" and "property have-nots".

The trend was alarming because it was accelerating.

"Home ownership has played a central role in the financial security of New Zealanders for generations, and the causes of declining home ownership need to be addressed now."

Mr Grant said the decline in Auckland showed the clear link between property prices and home ownership.

Auckland's median house price of $405,000 is the highest in the country.

The Real Estate Institute said this month that the national median house price was at a record high of $305,000.

Mr Grant cited the high number of new immigrants, a trend among younger people to marry and start families later, and the move towards contract and short-term employment for younger workers, resulting in less income certainty, as other reasons for the ownership drop.

Home ownership among New Zealanders aged 25 to 39 had dropped from 42 per cent to 32 per cent. the percentage of homeowners increased in line with annual income figures, but the largest income group home-ownership drop was in the $50,000-$60,000 income bracket - from 72 per cent to 55 per cent.

Mr Grant said this was probably where the "pain starts to be felt. If you do your sums on what you can afford on an income of $50-60,000 in Auckland, you'll see the difficulty."

Seventy per cent of New Zealanders who earned more than $80,000 a year owned their own homes, compared with 43 per cent of those on up to $40,000.

"The correlation between income and home ownership suggests that New Zealanders would choose to own their own home if they could," Mr Grant said.

Bob Hargreaves, property studies professor at Massey University, said Nielsen's figures appeared too high.

The number of rental tenancies had not increased dramatically, he said, which indicated a much less rapid decline in home ownership levels than the Nielsen survey showed.

The university's real estate analysis unit has issued figures showing a small increase in the number of new tenancies.

Housing Minister Chris Carter said new census figures on home ownership, due out soon, were expected to confirm the drop, putting nationwide home ownership at 63 per cent - not as low as the Wizard report.

Ten years ago, it was 75 per cent.

"It's a worrying trend, as that figure puts us below the United States, Britain, Canada and Australia," he said.

The Reserve Bank has raised questions about data in homeownership surveys generally, saying the number of trusts was rising and skewing the figures.

About 4 per cent of New Zealanders and 12 per cent of couples now have trusts, the bank said.

Professor Hargreaves he said the Nielsen research highlighted a "worrying" trend towards falling home ownership levels.

The age of people buying their first home was increasing, and it might not be uncommon soon for people in their 50s to be taking their first mortgage, he said.

Professor Hargreaves said that the mortgage on a house bought for $305,000 - the national median - would cost at least $470 a week.

Mr Carter said he was taking some options to the Cabinet this month on schemes that would help people buy their first home.