Most recently used as a fattening farm, it includes 3km of Kaipara Harbour frontage with riparian rights, a lake described as "a duck shooter's paradise", a woolshed, covered yards, barns and a four-bedroom house.
The sale had to be approved by the OIO because the land was deemed sensitive due to its size, waterfront location and rural nature. The sale was approved on July 4 but the decision has just been released.
The purchase, according to the OIO, includes 247ha of freehold land and a leasehold interest in about 5ha of land owned by Kiwirail as part of a railway corridor.
Colliers International, the real estate firm which handled the sale, said the property's vistas, easy contours and good road access made it suitable for further development or subdivision. It was also marketed via HouGarden.com, a property portal geared at Chinese speakers.
Mrs Wong is a shareholder or director in nine New Zealand companies, most of which are property related.
Other sales to overseas interests in the past year include 300ha of forestry land near Kaitaia to Japanese-owned Summit Forests, a 316ha farm and an 18ha waterfront property in the Kerikeri area to Swiss tobacco magnate Andre Calantzopoulos, and a 37ha property at Russell's Long Beach to former world number one tennis player Thomas Muster of Austria, known in his 1990s heyday as "the King of Clay".