One of the country's most controversial trade deals has passed its third reading, paving the way for access to up to 480 million consumers across 11 countries.

The passing of The Comprehensive Progressive Trans-Pacific Partnership (CPTPP) in Parliament this evening - with the support of all parties except the Greens - changes a number of laws to allow New Zealand to ratify the deal.

It will come into effect 60 days after New Zealand joins five other signatories - out of Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, Peru, Singapore, and Vietnam.- in ratifying the agreement.

"It goes beyond just reducing costs for business," said Minister of State for Trade and Export Growth Damien O'Connor during the third reading.

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"It contains the most comprehensive outcomes on labour and the environment that New Zealand has ever achieved in a trade agreement. These are legally enforceable for the first time."

The agreement has been the source of much controversy in recent years, with thousands of people taking to the streets in Auckland to protest the deal in 2016.

But the controversy has died down since Labour took power and renegotiated the deal in an attempt to, among other things, protect Treaty of Waitangi principles, Pharmac, and New Zealand's sovereignty.

Side letters have also been signed that narrow the scope for investor-state dispute settlement claims against New Zealand. They have been signed with Brunei Darussalam, Malaysia, Peru, Vietnam and Australia, and New Zealand also has an agreement with Canada and Chile to use ISDS responsibly.

O'Connor said the CPTPP would open access for exporters to 480 million consumers across 11 countries, including four with which New Zealand currently has no trade agreement.

It would also put New Zealand in a position to play a role in shaping the rules in the future global trade environment.

Notably, the Trump administration withdrew the US from the TPP in 2017, which thrust the deal into doubt.

But the remaining countries persisted and later that same year, the TPP was renamed the CPTPP after a number of changes were made to the deal.

These included revisions in the ISDS chapters, as well as changes to intellectual property rules.

This was welcomed by Prime Minister Jacinda Ardern, who said the Government wanted to take a different position on ISDS than its predecessors.

"We pushed hard, the message we got back was had we been at the negotiation table ourselves, even a year earlier, what a difference it would have made," she said at the time.

The Greens have been against the deal since its inception.

On Monday, the party's trade spokesperson Golriz Ghahraman reaffirmed the Greens' opposition to the deal.

"We've always opposed deals which prioritise money over the environment and working peoples' rights and continue to do so with this bill."