The numbers of houses for sale in Auckland and Canterbury are at "extremely low levels", while the national housing market remains tight, ASB economist Jane Turner says.
Low supply was likely to be weighing on turnover, with the lack of new listings probably responsible for the decline in sales.
The fall in the median number of days to sell also pointed to a supply-constrained market and, reflecting that house prices had lifted strongly over the past year, particularly in Auckland and Canterbury, Ms Turner said.
Real Estate Institute of New Zealand house sales fell 6.8% month-on-month in September, in an ASB seasonally adjusted estimate, although they remained 8% above year-ago levels.
Ms Turner believed the dip in turnover was due to lack of supply rather than easing demand.
A large drop in the median number of days to sell, compared with a year ago, suggested the pick-up in the housing market was broadening beyond Auckland and Canterbury.
In a statement yesterday, REINZ chief executive Helen O'Sullivan said a shortage of new listings was causing buyers to make rapid decisions, which was lifting prices.
The traditional rush of spring listings had not eventuated this year and the market was tightening as buyers faced a limited choice. That had been reflected by increases in the median price across much of the country.
Data from the REINZ showed there were 5653 unconditional sales last month, an increase of 418 sales (up 8%) compared with the same time last year, and a fall of 6.3% compared with August.
The national median house price increased by $1000 from $370,000 in August to $371,000 in September.
Eight regions recorded increases in sales volumes compared to September last year, with Central Otago-Lakes recording the highest, an increase of 25.9%.
Only Otago (up 12.8%) and Central Otago-Lakes (up 7.4%) recorded increases in sales in September compared with August.
Quotable Value, the government valuer, will release its monthly property values today.
