Homes are at their most affordable in six years - apart from in Auckland, where the average weekly mortgage is now more than $570 a week.
The Roost Home Loan Affordability report, issued today, shows Aucklanders need an average 10.4 years to save the 20 per cent deposit needed to buy a home - double the time for someone in Invercargill.
The report shows the average weekly mortgage payment on an Auckland house has risen to $572.47.
That means an Aucklander would pay 70.5 per cent of the region's average weekly wage - $812.04 take-home pay - on the mortgage for a median-priced Auckland house bought last month. This is up from 70.2 per cent in August.
Outside Auckland, affordability is worst in Wellington, Christchurch, Hamilton and Tauranga, the report shows.
But everywhere else, tax cuts, cheap money and flat house prices have made housing the most affordable it has been in six years.
Nationally, it now takes 58.1 per cent of a median after-tax income to repay a mortgage - the third consecutive drop in as many months and a level last seen in late 2004.
Whangarei improved substantially, and Invercargill reclaimed from Timaru the mantle of having the most affordable houses in the country.
"Home buyers have the wind at their backs as they head towards summer," said Roost spokeswoman Margaret Smith.
"Affordability is back now at levels last seen in late December 2004 - before the boom in house prices - because of improving incomes and lower interest rates."
But Bernard Hickey, of interest.co.nz which issues the Roost report, said Aucklanders were on the edge financially.
"You wouldn't want to lose your job or have to take a couple of weeks off work. If you want to buy a house, you're better off getting a job in Wanganui, Invercargill or even Whangarei," he said.
"You can buy a house in Auckland, but you can't afford to have a family."
Housing affordability slipped on the North Shore and the Auckland isthmus.
Prices were up because of the leaky building crisis and the areas' popularity with new migrants.
The average weekly mortgage in central Auckland is now $682.12; on the North Shore it is $680.22.
Leaky buildings were prevalent in these two areas, meaning prices of non-leaky homes were driven up by the shortage of that type of house, Mr Hickey said.
"We've had an entire generation of houses wiped out by leaky buildings and people are completely paranoid about them."
An influx of migrants had rejected buying in south and west Auckland, he said.
Nationally, the $29-a-week median tax cuts, mortgage interest rates of just over 6 per cent and a national median house price flat at $350,000 combined to improve affordability.
The median weekly take-home pay for a typical buyer was $765.75 last month, up 1.2 per cent from the $756.98 in September last year. Five years ago, median weekly take-home pay was $622.24.
Despite overall home affordability improving, house sale numbers remain low. Only 4323 housing sales were reported by the Real Estate Institute last month, one of the lowest figures for 10 years.
Last month's national median house price was $350,000, unchanged from August and the same as September last year.
Five years ago the median was $290,000.
Nationally, housing affordability might improve late this year as the tax cuts kick in and house prices flatten or fall.
Houses are described as affordable when 30 per cent of an income is needed to repay a mortgage.
A typical buyer is assumed to be in the 30-34 age group, and the 25-year mortgage is 80 per cent of the house price, partly floating, partly at fixed interest rates.
ANZ Property Focus said the slowing in the economy over the past few months was likely to make buyers more cautious.
Although fixed-term mortgage rates had fallen considerably since the start of the year, this did not appear to have had an appreciable effect on the housing market.
"Variable rate mortgages are still the best game in town but this may be changing."