Trade Minister Phil Goff has welcomed the United States decision to join negotiations with New Zealand and three other countries on a joint financial services and investment agreement.
The US Trade Representative Susan Schwab said the US would enter the talks with New Zealand, Singapore, Chile and Brunei- known as the P4 group of countries.
The P4 group signed a wide ranging free trade agreement in 2006, but this did not include financial and investment services and talks are set to begin to include them in the agreement.
The US already has free trade deals with Chile and Singapore and Ms Schwab said it would also consider joining the wider P4 agreement.
"The administration will hold consultations on this proposal with Congress and a wide array of stakeholders over the coming months," Ms Schwab said.
"Participation could provide a pathway to broader Asia-Pacific regional economic integration with like minded countries committed to high-standard agreements."
Mr Goff said Ms Schwab's announcement was significant as the US joining P4 would contribute towards achieving New Zealand's long-standing objective to liberalise trade between the two countries.
"The P4 was designed to allow participation by others in the region. The involvement of the US would give it critical mass and encourage others to participate in it," Mr Goff said.
The US is New Zealand's second-biggest export market.
New Zealand has long sought free trade deals with the US, but has so far been unsuccessful in even getting an agreement to have talks.
