An earthquake and a tax rise have combined to push house sale volumes to a 10-year low, as one major trading bank hints at zero-per cent deposits to lure new homebuyers.

Real Estate Institute data for September - out yesterday - shows the annual spring sales bounce failed to materialise, holding the median price at $350,000.

Most Auckland suburban areas showed slight price rises from August and September, but institute spokesman Bryan Thomson said national volumes were at their lowest for at least a decade.

House sales totalled 4323 last month, less than half the number for September 2006, when the market was booming.

Mr Thomson blamed uncertainty over tax changes and the Canterbury earthquake.

The gloomy figures came as ASB launched an advertising campaign hinting that borrowers might no longer require a one-fifth deposit to get finance

The ad, which ran in the Herald yesterday, promised "we can help if you don't have 20 per cent deposit. That should calm you down 100 per cent."

However, a check revealed the bank was now prepared to loan up to 90 per cent, as long as the customer's income was "sufficient to the bank's requirement" and the property was stand-alone and owner-occupied.

JB Weir strategist Bernard Doyle yesterday said the ASB campaign could be a sign the institution was "trying to stimulate demand".

Lower bond yields overseas had helped trigger a drop in the two-year fixed rate, from 7.4 per cent to 6.6 per cent in recent months.

However, the lowering rate had failed to carry through to the house market, he said.

"The housing market has been left behind somewhat. This is a house market that probably needs a fair bit of encouragement to be ticking along.

Massey University banking expert David Tripe agreed the advertisement was a ploy to lure customers, but did not believe it showed a greatly increased willingness to loan money.

The advertisement simply meant anyone with less than a 20 per cent deposit would likely get a better reception than the usual "resolute and absolute no", he said.

Banks approached by the Herald yesterday said they routinely considered loans on deposits of less than 20 per cent, though ANZ/National Bank was offering a further $1000 to help customers with mortgage costs.

"Spring is a time when people start getting interested in the housing market again, and we wanted to give people an extra helping hand in the current economic climate - if they were thinking of refinancing their mortgage or buying a new home or their first home.

"While we have offered contributions before this is more than usual," a bank spokeswoman said.

Darren Gibbs of Deutsche Bank said the housing market had stayed depressed. "After allowing for seasonal and trading day factors, the number of house sales fell about 5 per cent during the month, down 34 per cent year-on-year."

Chris Tennent-Brown of ASB noted the swelling numbers of of unsold houses.

"Until recently, low turnover has been matched by relatively low listings. This has helped support prices. Our inventory measure shows that based on current listings and monthly turnover, there is a steady extension in the months to sell total listings over 2010. This measure, which excludes Canterbury, has extended to 13.9 months, up from last month's 12.8 months. This figure is now getting quite high and well off the trough of eight months of inventory at the end of last winter," he said.

* Northland: August $310,000 - September $300,000
* Hibiscus Coast: August $460,000 - September $467,000
* Rodney: August $450,000 - September $447,500
* North Shore: August $520,000 - September $530,000
* Auckland City: August $485,500 - September $525,000
* Waitakere: August $375,000 - September $380,000
* Manukau: August $441,750 - September $420,000
* Tauranga: August $353,000 - September $328,000
* Rotorua: August $285,000 - September $231,500
* Wellington: August $397,500 - September $398,500
* Christchurch: August $335,000 - September $338,000

* Dunedin: August $245,000 - September $242,000

* New Zealand: August $350,000 - September $350,000

Source: Real Estate Institute of NZ