National median has risen $9000 to $370,000 in just a month.
Home owners with big mortgages can breathe a sign of relief - interest rates seem destined to stay low, despite a springtime house-price surge.
ANZ senior economist Sharon Zollner says interest rates are likely to stay down because the Reserve Bank is content to remain on the sidelines as rising house prices are not flowing through into economic activity or broadening inflationary pressure.
But whether the market continues to build up a head of steam and home owners start spending more, banking on price rises continuing, is uncertain, she says.
The Real Estate Institute said that from July to August, sales volumes nationally rose 16 per cent and the national median shot up $9000, from $361,000 to $370,000, one of the biggest jumps seen.
Agents sold 6035 properties in August, up 843 on July and all regions recorded volume rises.
Sales' volume in the Auckland region rose 25 per cent and the city showed a record median price of $505,500, up 1.1 per cent on July and 11.6 per cent on last August.
See a regional breakdown of the latest REINZ property stats here.
Real Estate Institute chief Helen O'Sullivan said Auckland properties sold fast in just 30 days, compared with 33 days this time last year.
The continued improvement in the number of days to sell underlines the tightness of the market.
"The continuing theme for Auckland is strong buyer demand for properties with multiple offers increasingly common.
"During the month, more than one-third of sales were completed via auction, setting a new record for this type of sales method," she said.
Tony McPherson, REINZ regional director for the Canterbury/Westland region, said sales volumes across his region were flat and Christchurch sales dropped 3 per cent from July to August, but rose in Rangiora and mid-Canterbury.
Christchurch prices jumped by a median $15,000 in the past year but Mr McPherson said that rapid growth had now eased.
Nationally, houses took 38 days to sell in July but that decreased to 35 days last month. The Real Estate Institute said 1110 dwellings sold throughout NZ by auction last month.
Last month, 252 properties sold for $1 million-plus, 912 for $600,000 to $999,999, 1507 for $400,000 to $599,999 and 3364 for less than $400,000.
By Anne Gibson @Anne Gibson Email Anne