September sales at the country's largest real estate agency were down 12.6% compared to a year ago, and average prices were down in Auckland and Christchurch but up elsewhere.
Harcourts sold 1741 residential properties throughout the country in September, down 252 from 1993 in September last year.
The national average selling price was $573,392, up 1% compared to September 2016.
However there were big regional differences.
In Auckland the number of sales was down 15% compared to a year earlier, while the average selling price dropped from $953,997 in September last year to $935,927 in September this year, (-1.8%).
That compares with average selling prices of more than $1 million earlier this year.
In the Wellington region the number of sales in September was down 13.6% compared to a year earlier while the average selling price was up just 1%.
In Christchurch sales were down 11% compared to September last year, while the average selling price was down 4%.
However while the number of properties being sold is decreasing, the number of homes on the market is increasing, giving potential buyers more choice.
Harcourts had 6119 residential properties available for sale at the end of September, up 2.4% compared to September last year.
But its Auckland offices had 25% more properties available for sale at the end of September than they did in September 2016.
The number of properties auctioned by Harcourts in September was down 36.9% compared to a year earlier.
Harcourts chief executive Chris Kennedy said the market was still strong despite the fall in the number of sales.
"We are still in a good market, it's just in a different place to where it was 18 months ago during the frenzied peak," he said.
"If a vendor's expectations are reasonable, their property will sell."