New Zealand will host the next round of Trans Pacific Partnership (TPP) trade talks in December.
Hundreds of negotiators from around the Asia Pacific region will attend the nine-day meeting in Auckland from December 3.
Trade Minister Tim Groser said he was pleased New Zealand would play a central role in welcoming Canada and Mexico to the talks, which would create New Zealand's largest free trade area.
Their addition marked a significant turning point in the negotiations and aligned with the original vision to create a comprehensive regional trade and investment agreement, he said.
Canada and Mexico would add a further $1 billion of exports to the agreement, growing the proportion of New Zealand trade covered by the TPP to $18b.
Mr Groser said a programme would be prepared for stakeholders with an interest in the Trans Pacific Partnership.
"We know that there is strong public interest in TPP and that a number of stakeholders, representing a diverse range of views, will want to play a part in the round."
The announcement follows a recent meeting of TPP trade ministers in the margins of the Apec meeting in Russia.
"We reaffirmed our collective goal to work for an agreement that eliminates tariffs and includes truly regional rules to support supply chains and grow trade.
"Achieving this result will boost export growth and support job creation in New Zealand," Mr Groser said.