New Zealand's national median house price has surpassed $500,000 for the first time, as demand continues to outstrip supply.

Photo: 123RF

The Real Estate Institute of New Zealand (REINZ) released the seasonally adjusted national median house price today. It had risen 10 percent to $506,000 in May, up 3 percent compared to April.

Record prices were reached in several regions, including Bay of Plenty, Waikato, Taranaki, Wellington, Canterbury-Westland and Central Otago Lakes.

REINZ director Bryan Thomson said national inventories had fallen more than 40 percent compared to a year ago.

"The market continues to be very active right across New Zealand and there is a building shortage of listings available for purchase," he said.

"I think that's the stand-out statistic at the moment - right now, listing numbers are below what demand would want them to be."

There were just over 9000 residential sales in May, which was 14 percent up on the year earlier.

However, the volume of May's sales was down a seasonally adjusted 5 percent on April, as the supply of houses continued to fall.

Mortgage advisor Bruce Patten said the Reserve Bank would be considering extending current restrictions on Auckland property investors to the rest of the country.

"With this sort of data, I've think they've got enough ammunition to justify probably pushing it through the rest of the country now.

"What it'll be interesting to see is how far-reaching they decide to take things full stop - so whether they see this as a big enough risk to, you know, put in some more measures."