Investors from the United States were the largest overseas purchasers of land in New Zealand between 2013 and 2015, analysis of Overseas Investment Office approvals shows.

The study shows the US bought 40 per cent of office-approved land sales while China purchased 11 per cent, and Hong Kong bought 7 per cent.

The authors of the KPMG study, Foreign Direct Investment in New Zealand, say that forestry transactions are the most significant, rather than dairy or agribusiness.

The US and Canada were the most significant source of foreign direct investment over the three years, with the US providing 17 per cent, Canada 15 per cent, Australia 12 per cent and China 9 per cent.

This may downplay Australia's involvement because NZ investment below $496 million which doesn't involve a fishing quota or sensitive land no longer requires OIO approval.

The majority of overseas transactions involving New Zealand assets or companies "are between an offshore vendor and an offshore investor", the authors add.

Total investment in New Zealand by overseas investors for the three years was $26.3 billion. The largest transaction was the sale of listed consumer goods company Goodman Fielder in February 2015, for $1.27b. The dominant vendors were Australian, while the new owners are based in Singapore and Hong Kong.

Chinese investment into New Zealand was overwhelmingly focused on energy, power and utilities, with the sector making up 70 per cent of all investment. By contrast, agribusiness was just 16 per cent. However, agribusiness made up four of the top 10 transactions made by China over the period.

Breaking down the agribusiness sector, investment in dairy and milk processing made up 38 per cent of investment, reflecting a period in which dairy prices peaked. Forestry made up 17 per cent, wine 14 per cent, and beef and sheep 9 per cent.

China was the largest foreign investor in dairy at 28 per cent, with France the second largest investor on 13 per cent. Total investment in agri-business was $3.4b.