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.