The Labour Party says it may defy the Trans Pacific Partnership's rules on property sales if it enters Government.
Finance spokesman Grant Robertson said his party wanted to reserve the right to legislate in the best interests of New Zealanders.
"We think it is in the best interests of New Zealanders to give all of us a fair go in buying our own home," he told Radio New Zealand.
"If that requires passing legislation to limit overseas buyers from purchasing land and housing then we want to be able to go ahead."