Auckland's biggest real estate company sold about 25 percent fewer houses in December compared with a year earlier, although prices remain stable.
The Barfoot and Thompson sales figures showed 796 houses were sold in December, compared with 1050 for the same time a year earlier.
The number of sales was the company's lowest for December in four years.
However, average prices were up on the same period last year, to nearly $870,000 from $758,891. As well, 278 properties sold for more than $1 million.
Barfoot and Thompson managing director Peter Thompson said Auckland's growing population and the number of new builds failing to keep pace with demand meant competition for properties was likely to remain strong in the first quarter of this year.
Mr Thompson said the market was still constrained by a lack of supply but he did not believe the average price would rise as much as it did last year.
"For the last three to four years we have seen the average sale price increase between 10 and 14 percent. I don't think this will continue - if we get a 5 percent increase this year I will be surprised."
Mr Thompson said sales data for December has sent mixed messages as to where the market will head in 2016.
"January's sales data is always influenced by the summer holiday period. It will be March before we can get a clearer understanding of where 2016 will head."