Trade Minister Tim Groser says there is no relevance to New Zealand from an Australian government report showing that free trade deals have failed to deliver the benefits promised.
New Zealand is currently involved in negotiations on the Trans-Pacific Partnership trade deal, but the Green Party says that because of a lack of analysis the benefits of such arrangements are unclear.
Co-leader Russel Norman says the benefits could be small and come with large costs, such as giving foreign companies the right to sue the New Zealand government.
Mr Groser acknowledges analysis of some previous deals would not have shown economic benefits.
But he says they led to larger deals that had definite payoffs for New Zealand companies.