The Maori Party has added its voice to calls for restrictions on foreign ownership of New Zealand land.

Several large international firms are looking at buying land here - the highest profile being Crafar farms.

Foreign companies need to get approval from the Overseas Investment Office.

Recently Prime Minister John Key said he understood the concerns.

"As a general and broader principle I think New Zealanders should be concerned if we sell huge tracts of our productive land.

"Now, that's a challenging issue given the state of the current law and quite clearly it's evidentially possible and has been achieved that individual farms can be sold. Looking four, five, 10 years into the future I'd hate to see New Zealanders as tenants in their own country and that is a risk I think if we sell out our entire productive base, so that's something the Government will have to consider."

Maori Party MP Hone Harawira said he was thinking of drafting a bill banning sale of land to foreigners.

The Greens have previously suggested leasing be possible but not ownership.

"About 27 million hectares of Aotearoa's prime real estate has been sold off to foreigners under both National and Labour, and that policy is simply not in the best interests of the citizens of Aotearoa, Maori or otherwise," Harawira said.

"If foreigners want to do business or have a holiday house here, that's fine - let them lease or pay rent."

Countries like China, Japan, Thailand, parts of Europe and several Pacific Island nations allowed foreigners to have "land use rights" but not freehold title, he said.

- NZPA