The growth in house prices slowed last month but a lack of supply remains the main driver of the market.
The Real Estate Institute's latest data shows the national median house price fell two percent to $492,000 in August from July's record $505,000.
The annual growth rate also slowed to 6 percent from 9 percent.
REINZ director Bryan Thomson said a lack of stock, with listings down 18 percent on a year ago, remained the main influence on the market.
"The underlying trends indicate that the struggle for stock is the single biggest factor driving market behaviour and price expectations across the country, as we await spring listings."
However Auckland house prices remained at record levels, gaining 14 percent to a median $842,500.
Mr Thomson said there were signs the Reserve Bank's tighter lending rules for low deposit mortgages had affected behaviour, but the momentum in the market remained strong and widespread throughout the country.