A Trans Pacific Partnership (TPP) would be "transformational" for both New Zealand agriculture and the country's economy, Federated Farmers national president Bruce Wills says.
Leaders of the nine countries involved in TPP negotiations have agreed on the broad outlines of the deal.
A TPP could boost New Zealand's exports to the United States "enormously" and that was only one partner, Mr Wills said.
"The sky is the limit given HSBC Bank says our trade with the rest of the world could grow 83% in the next 15 years.
"That outperforms the global average and is vital for us to remain a first-world nation and for public services to remain properly funded."
The potential was "huge" because the TPP would involve five of the country's top 10 export partners, including three of the top four.
The removal of trade barriers for agriculture was crucial and a "non-negotiable requirement" for Federated Farmers as the world needed to eliminate tariffs and subsidies. Free trade also needed a wider genuine commitment to services, investment and intellectual property, he said.
Fonterra also welcomed the release of the broad outlines, saying a comprehensive agreement covering all sectors had considerable potential to liberalise dairy trade to meet the existing and quickly growing demand in the TPP member countries.
The Asia-Pacific region was already a major market for the dairy co-operative and was expected to be a major growth area, group director for supplier and external relations Kelvin Wickham said.
"We see a high-quality outcome for dairy as a crucial part of Japan joining the TPP," he said.