Auckland residential property sales volumes have fallen to the lowest April level in four years, according to the city's largest real estate agency.

There were 944 sales in April, which was down 12 per cent on the same month in 2016 and down 30 per cent on March's figure, Barfoot & Thompson said.

The agency said its 1,496 new listings in April were down 5.3 per cent from a year earlier and 20 per cent lower than March.

It had just 2,846 properties on its books at the end of April, the third consecutive monthly decline and the lowest level for April in more than 15 years.

April's average Auckland sale price of $NZ873,599 ($A806,982) is 8.6 per cent higher than April 2016, lagging behind the 12 per cent rate over the past year, and just 0.8 per cent higher than March, Barfoot said.

The government and New Zealand's Reserve Bank in 2015 introduced measures to cool Auckland's bubbling property market, where migrants and investors are adding to competition for a shortage of housing.

RBNZ governor Graeme Wheeler last week kept the benchmark interest rate unchanged, noting there were some indications that house price inflation in Auckland may be picking up. However, Barfoot said its data suggested Auckland house prices had pulled back from breaking into new territory.

"Overall, activity in April is best described as restrained," said managing director Peter Thompson.

"The likely cause of this was caution around current pricing and the low number of properties on the market, restricting choice."

The median sales price for the month at $NZ820,000 was up 2.8 per cent on that for March, and 8.8 per cent higher than April 2015.