Auckland's average house price rose in June while the volume of sales fell, according to realtor Barfoot & Thompson, which said the market was still characterised by "very tight supply".

The average sales price rose 3.9 per cent to $NZ908,343 ($A871,605) in June from May, to be 9.9 per cent higher than in June 2015, based on sales data from Barfoot, the city’s largest real estate firm.

The median price was $NZ839,500 in June, up 3.7 per cent from May and an increase of 6.1 per cent from a year earlier.

Barfoot’s sales fell about 11 per cent to 1,168 in June from May. It had sales of 1,167 in June last year.

The Real Estate Institute hasn’t yet released its monthly figures for June after reporting that the median national sale price jumped 10 per cent to a record $NZ506,000 in May from a year earlier.

Five regions hit record high median prices in the latest REINZ data, although Auckland’s annual rate of increase lagged behind the national average at 7.5 per cent to $NZ805,000.

The Reserve Bank said on June 9 that the high level of house prices relative to incomes in Auckland and accelerating house price inflation in other parts of the country was a concern from a financial stability perspective and warranted close attention.

Deputy governor Grant Spencer is scheduled to speak about macro-prudential policy and housing market risk in a recent speech.

Barfoot’s new listings fell 7 per cent from May to 1,170 in June, which the firm said conformed to seasonal norms.

Almost half the properties it sold in June, or 446, were in excess of $NZ1 million, while 67 sold for less than $NZ500,000.