The rate of rise in house prices is showing only very minor signs of slowing.

The Real Estate Institute's House Price Index, which measures the changing value of property in the market, rose 29.8 per cent in the year ended June compared with an annual rate of nearly 30 per cent in May.

The national median price rose a seasonally adjusted 28.7 per cent over the year earlier, to $820,000.

"Once more, we're seeing this story echoed by some very strong results in the REINZ House Price Index (HPI), which again reached a new high on the index," says REINZ chief executive Jen Baird.

Prices hit record levels in four regions, with growth strongest in Malborough where prices rose by more than half to $705,000.

The median price excluding Auckland increased 25.9 per cent from $540,000 in June last year, to $680,000.

The number of houses sold was up 6.2 per cent on the month before from 6913 to 7345, which is the highest for a June month in five years.

The average number of days taken to sell a property fell from 46 days to 31.

"Those buyers hoping for a bargain over winter might be disappointed, and today's data really points to how important it is to address the housing supply issues we have," says Baird.

The lack of stock remained a key prop for prices, with fewer than 14,000 houses available for sale, compared with about 21,000 a year ago.

Baird says the introduction of various measures to try to cool the property market was yet to have a material impact, as the June property data points to underlying strength the market.

"Reports from agents around the country are that there are still good numbers of attendees at auctions and open homes; and that both first time buyers and investors are still relatively active in the market."

Sales volumes are expected to continue at a solid level for the next couple of months unless there are any changes in the underlying fundamentals, she says.

-RNZ.