The Overseas Investment Office has approved sales of more than 17 per cent of Auckland's commercial land and 6 per cent of its industrial land to foreigners in the past seven years.
Auckland had the highest portion of commercial land to get the office's consent for sale during that time. Bay of Plenty was next, at 5.8 per cent.
The national average portion of commercial land involved was 1.91 per cent for a total of 600ha, said Terralink International, a property intelligence company which examined consents details obtained under the Official Information Act.
For industrial land, the national average for which consent was granted was 4.88 per cent, or 1600 ha.
Terralink managing director Mike Donald said the analysis was to give the public a "reality check" about the extent of foreign ownership.
"New Zealanders have no easy way of knowing how much of their land is currently foreign owned, so there is a lot of speculation and uncertainty."
Although farm sales had grabbed public attention, consents for sales in Auckland and nationally made up about 1.5 per cent of the total rural land area. The consents figures included 3500ha of Auckland rural land and 200ha of lifestyle blocks.
Mr Donald said it was unknown how many deals for lease or purchase went ahead or land was later resold to a local buyer.
Auckland Chamber of Commerce chief executive Michael Barnett said foreign firms heading to Auckland to invest in distribution networks and manufacturing were creating jobs and international trade prospects.
Investors from South-east Asia formed the biggest segment of the Auckland market, followed closely by Europeans and Australians, said Bayleys Real Estate managing director Mike Bayley.
Investors looked to hold on to properties for the longer term rather than take short-term capital gains when the market peaked.
"Interest from offshore parties continues to remain firm - particularly in the $10 million-plus price range."
Mr Bayley said Auckland was seen as a safe investment and giving steadier long-term growth than the unpredictable markets of glamour cities such as London, Moscow, Hong Kong, Tokyo or Rio de Janiero.
Overseas money was necessary to give the best returns to local vendors.
The OIO does not cap the amount of land that can be bought.