Prime Minister John Key says the Trans Pacific Partnership will not technically prevent a future Labour Government from banning the sale of residential properties to foreigners.
But breaching the trade deal's obligations could lead to a legal challenge from other countries, he said this afternoon.
The 12-nation agreement includes a non-discrimination provision which says New Zealand cannot ban Trans Pacific Partnership (TPP) countries from buying New Zealand property.
Labour leader Andrew Little says Labour will flout this rule if it enters Government because it believes a ban on foreign ownership of houses is in the best interests of New Zealanders.
Mr Key told reporters at his weekly press conference that there was nothing to stop future governments from going against the TPP's provisions.