A warning Labour's plans to ban the sale of property to foreign investors could put our trade agreements in jeopardy.

The New Zealand Institute of Economic Research said under the trade agreement we have with Korea and China, it's not possible to ban foreigners buying homes here.

Deputy Chief Executive John Ballingall said it would be a breech of our free trade agreement obligations.

"This creates a bit of a challenge, unless Labour is suggesting that they are going to renegotiate some of these agreements to allow us to impose such a ban, which seems unlikely, then it seems a very difficult policy to try and implement."

There's also been a call for the re-establishment of bipartisan trade policy to support Kiwi businesses.

Ballingall said the long-cherished bipartisan trade policy has been damaged in recent years’ debates over the Trans-Pacific Partnership

He said businesses want certainty.

"They want better access for our exports and that is best achieved if we have bipartisan trade policy support from across the political spectrum."