ASB senior economist Mark Smith has researched Statistics New Zealand data on home transfers, released three weeks ago.
He said the Government had to "strike the right balance" between encouraging house building and ensuring New Zealanders were not priced out of the market.
Mr Smith said there were indications of segmentation in the housing market, as an increasing number of purchases were made by New Zealand residents, who are not citizens. Trends in resident and non-resident sales and purchases could not be identified at present as there was not enough historical data, he said.
"We suspect, however, that over time overseas influences will slowly continue to exert greater influence on the residential property market and property market valuations."
Nationally, corporates had a 10.4% share of house transfers, but that figure was higher in some areas, including Queenstown Lakes (16.2%), Auckland (14.3%), Hamilton (13.9%) and Christchurch (12.4%).
Mr Smith welcomed the new SNZ data but said there were "gaps and limitations" in what has typically been a "grey area" in New Zealand’s economic analysis.
The initial data suggested about 3% of nationwide purchases for the year to March were made by non-residents.
"This was in a similar ballpark to previously published figures," Mr Smith said. Between 11% and 21% of the reported purchases involved a non-New Zealand citizen, he said, and the numbers were considerably higher in the Queenstown and Auckland markets.
"For policymakers, the figures suggest measures to restrict net immigration and overseas demand could have a significant impact on the local property market."
Trade Minister David Parker recently relaxed a ban on foreign buyers relating to apartment developments, largely because some developments could not get off the ground without pre-sales to foreign interests.
The ban had allowed foreigners to buy apartments off the plan but they had to sell them after construction. Now they can keep an apartment if the development has more than 20 units.
Because of existing free trade agreements, Singapore nationals joined Australians as exempt.Mr Smith said greater participation by overseas investors in the domestic property market suggested policy initiatives directed at slowing the overseas demand could potentially have a "significant impact".
However, he believed increased overseas investment had likely contributed to more residential construction.
"Recent government announcements relaxing ownership requirements on apartments look to be a step in the right direction."
For the quarter to March, 76% of property transactions were made by New Zealand citizens, and almost 16% were corporate purchases.
"Details of corporate buyers and sellers were not published, as in many cases citizenship details were not available," Mr Smith said.
However, he believed most would have been New Zealand citizens.
Other "gaps" included data on purchases of residential sections and the exemption of Maori land and Treaty of Waitangi settlements, he said.
