The Government has the numbers it needs to pass any enabling legislation to ratify the Trans-Pacific Partnership (TPP).
The agreement will be signed next week in Auckland, after which the 12 nations involved will have up to two years to complete domestic ratification processes before the agreement comes into force.
The shape that legislation will take through the New Zealand Parliament is not yet clear, but with Labour's Phil Goff having permission to cross the floor, and the support of ACT and United Future, the Government has the numbers it needs.
ACT party leader David Seymour said supporting the TPP was a no-brainer.
"It means enormous advances in market access, it mean investment, jobs and growth for the New Zealand economy.
"I think it is a very exciting thing and we should be particularly proud that New Zealand has actually played the leading role in bringing together some of the largest economies in the world."
United Future leader Peter Dunne said he would also support any TPP legislation that came before Parliament.
"The TPPA is an agreement that is vital for New Zealand's long-term interests and we cannot afford to not be part of it.
"The legislation that Parliament is likely to pass will relate to consequential changes and assuming it follows the spirit of similar legislation post other agreements, is likely to be of itself relatively non-contentious.
"New Zealand cannot step off the world at this point and not join the TPPA, we lose all our markets frankly if we do that."
After next Thursday's signing, the government will hold a series of roadshows around the country it says will help businesses identify and plan for new export opportunities when the TPP comes into force.