Peters has campaigned hard against land, asset and company sales to foreign investors - in particular farms and other productive land, major companies such as Silver Fern Farms and infrastructure.
NZ First wants strict controls on foreign ownership, including restricting sales of residential land and farmland to New Zealand citizens, permanent residents who were living in New Zealand and companies which were majority NZ owned.
It also wanted a comprehensive register of foreign ownership of land and a ban on the further sale of state assets to overseas buyers.
While Labour is also opposed to sales of farmland, residential property and strategic assets to overseas investors, National is more open to it saying it brings much needed investment into New Zealand.
It has argued Overseas Investment Office subjects sales to rigorous investigation and conditions prior to approving sales - conditions that can deliver benefits beyond what a sale to a New Zealander would offer. However, National has not said it would be deal breaker.
Meeting Peters' requirements was possible through significant changes to the Overseas Investment Act around the classifications of what was "sensitive" land and "significant business assets".
Another barrier was likely to be existing free trade agreements which allow citizens from countries New Zealand has an agreement with to buy land.
Labour leader Jacinda Ardern has said she wants to reopen negotiations on the Trans Pacific Partnership and the South Korea free trade agreements to give New Zealand a carve-out for Labour's policy to ban foreign land buyers.
NZ First is also opposed to the TPP, in particular because of the investor state disputes settlement provisions but it also wants to ensure agreements under negotiation protect land and strategic assets, and renegotiate "poor quality" deals.
Labour's policy states it is opposed to the sale of "farms, homes, state-owned enterprises, and monopoly infrastructure" to overseas buyers. It has also proposed stricter Overseas Investment Office rules in other areas, such as requiring the sale of logging rights on land over 50ha to be approved by the OIO.
Currently Overseas Investment Office approval is required for sales of farm land that exceeds 5ha, land adjoining conservation areas or reserves, and land that is next to a foreshore. In cases where the person does not intend to live in New Zealand, they must show a clear benefit to New Zealand from the purchase, such as through conservation efforts and jobs.
Consent is also required for assets or securities selling for more than $100 million or when establishing a business with expenditure of more than $100 million.
Investors also have to meet criteria around business acumen, financial commitment, character and must not have been deported or ineligible to enter New Zealander under immigration laws because of an issue such as a criminal conviction.
