Foreigners own far more farmland than officially estimated and could hold a tenth of our country's productive agricultural real estate, an economist says.

Bill Rosenberg of the Council for Trade Unions disputed land information company Terralink's estimate that under 1.5 per cent of rural land was in foreign hands, material which was based on Overseas Investment Office (OIO) data.

"That only looked at land purchases over the last seven years so misses any land held before that, and ignores all the substantial data problems in making such estimates," Rosenberg said.

"For example, [Terralink's] definition of rural land appears to exclude forestry and confuses rural land with the OIO's classification of agricultural land which itself is misleading."


"I analysed these matters carefully and concluded the overseas ownership of land was at least 8.7 per cent of farmland, including forestry land, and could well be 10 per cent."

Terralink said proportionally more of the country's industrial and commercial land is being sold to foreigners than any other land.

Rosenberg and others are also worried about foreigners snapping up houses. "There are essentially no restrictions on buying urban land unless on foreshore, adjacent to conservation land [and so forth]," he said.