A shortage of new listings is causing house prices to go up as buyers are forced to make rapid decisions, said REINZ chief executive Helen O'Sullivan.
"The traditional rush of spring listings has not eventuated this year and the market is tightening as buyers face a limited choice of offerings.
"This has been reflected by increases in the median price across much of the country."
The national median house price increased 0.3 per cent from $370,000 in August to $371,000 in September.
In Auckland, the median house price moved up 1.9 per cent compared to August. That marked a new record median price of $515,000.
"Auckland continues to be the key region in terms of price increases and demand for housing," O'Sullivan said.
"However, other regions are now starting to see pressure building with the median price in five regions within 10 per cent of their record medians and the number of days to sell falling quite rapidly in some parts of the country."
Nelson/Marlborough also reached a new record median price of $353,000.
For a regional breakdown of REINZ property statistics, click here.
The national median house price last month was 6 per cent higher than September last year and $1,000 below the record median price, set in June this year.
Days to sell has fallen by 13 days since February (46 days to 33 days).
Of all sales in September, 20 per cent were auction sales, a new national record.
ASB economist Jane Turner described the housing market as tight, particularly in Auckland and Canterbury where inventory levels are now "extremely low".
"We believe the dip in turnover in September is due to lack of supply rather than easing demand," she said.
"New house listings remain low and the total stock of houses available for sale continues to decline."
The fall in the median number of days to sell also points to a supply constrained market, she said.
The REINZ stratified house price index is up 5 per cent on a year ago.
"Over September, the index lifted slightly, although was flat once seasonally adjusted."
This appeared to be due to a decline Canterbury house prices, she commented.
"Monthly data can be volatile, so we are reluctant to put too much weight on this movement.
"However, this is a development we will be watching closely. As construction commences in Canterbury and housing supply starts to increase, pressure on Canterbury house prices is likely to ease."
