On a seasonally adjusted basis, the median price fell 4 per cent compared to July, indicating that the decrease in median price was greater than expected.
The number of houses sold in Northland in August fell 7 per cent compared with July and 29 per cent since August 2016.
REINZ figures show 252 properties were sold in August last year but only 178 changed ownership last month.
From the 178, 94 were sold in Whangarei, 60 in the Far North and 24 in Kaipara.
REINZ chief executive Bindi Norwell said the Northland housing market had a slow down for a couple of months, but buyers were back again.
"Listings remain slow, but those that are on the market are selling well in part due to vendors' expectations becoming more realistic, but also due to a 10 per cent increase in attendees at open homes."
The number of days to sell in Northland eased by one day compared to July, from 46 days in July to 47 days in August.
The number of days to sell eased by 10 days compared to August 2016.
Over the past 10 years the average number of days to sell during August for Northland has been 66 days.
The number of properties sold across the country fell by 20 per cent during August and regions with the biggest fall were Southland (37.3 per cent), Northland (29.4 per cent), Taranaki (25.9 per cent), Waikato (25 per cent) and Auckland (21.5 per cent).
Ms Norwell said banks' lending criteria and Loan-to-Value ratios (LVRs) were still impacting first home buyers and investors.
"If you looked at the number of properties sold, without looking at the bigger picture, one might assume that the market was showing significant signs of slowing. However, as prices are holding up, and even increasing, then it suggests that people may be holding off from selling their property unless it's absolutely necessary," she said.
