Transcript
The agreement, known as PACER Plus, is a deal between the countries of the Pacific Islands Forum and Australia and New Zealand.
It's been negotiated for nine years, and is touted by proponents as a new form of deal that's as much about development as it is trade.
New Zealand's trade minister Todd McClay says PACER Plus will give funding to boost exports from Pacific countries, and creates rules to make it easier for the region's countries to trade.
"It's a high quality agreement that gives certainty to exporters but really will help the Pacific Island countries meet some of the requirements of international trade. What that really means is they can transform and modernise their economies, they can look at trade-related infrastructure, they can meet the requirements and rules that trading nations of the world now demand."
But there's also been strong opposition to the deal - from churches, politicians and civil society groups.
They say the deal threatens the fragile economies of island countries, and removes governments' abilities to extract revenue and protect their own interests and resouces.
Critics also say the deal is unbalanced towards Australia and New Zealand, and cements their economic dominance in the face of greater interest from other powers in the region.
Those are views shared by three of the region's largest economies - Fiji, Papua New Guinea, and Vanuatu - who are refusing to sign the agreement.
Steven Siro, from the Office of the Chief Trade Advisor, the region's trade body, acknowledges not having the three large economies does weaken the deal somewhat.
"Yeah it does in some ways, but then there are some countries - even though they are relatively smaller - who are willing and eager to complete this process. In the long run we are hopeful that all three countries - PNG, Fiji, and Vanuatu, would acceed at a later date."
Fiji and Papua New Guinea say they will not sign until parts of the deal are renegotiated and rewritten, which Mr Siro says will be difficult to do.
However, Mr McClay says he's not worried by the refusal, and PACER Plus will always be a flexible work in progress.
"I'm quite relaxed about them not being ready to come on board at the moment. After all, this is not about forcing peoples' hand. It's about partnership and they will see over time the benefits of the agreement, and for any country that's not ready the door remains open for them to sign when they are."
Despite the debate's polarisation, an analyst of Pacific issues says the claims of both sides are probably overblown.
TNC Pacific Consulting's Tess Newton Cain says it's unlikely the deal will undermine export industries.
On the other hand, she also says many Pacific countries already have tariff-free entry, and the deal doesn't do a lot to remove the barriers that do exist.
"Those are things around improving the productive sectors, improving access via biosecurity and phyto-sanitation rules. Those will still need to be addressed through other means, whether it's through the aid for trade development assistance part of the deal or elsewhere."
Either way, trade advocates from around the region will be celebrating on Wednesday, as the deal is finally signed after nine years of talks.
This is Jamie Tahana.