Negotiators from 11 countries are gathering in Auckland this morning for the 15th round of the Trans-Pacific Partnership talks.
For a week-and-a-half they'll work towards establishing an Asia-Pacific free trade deal.
But protesters say these negotiations are too secretive and are being driven by large US corporations.
As the talks at Sky City began this morning, protesters made themselves heard outside.
"I'd like to see the text at least out in open," says First Union retail secretary Maxine Gay. "If this is such a great deal why does it have to be so secret?"
Eleven countries are involved in the talks - the US, Australia, Singapore, Brunei, Vietnam, Malaysia, Chile, Peru, and for the first time Mexico and Canada.
But critics say these talks are being driven by large US corporations who want a firmer grip on intellectual property.
"The track record of US free trade deals show they are done in the interests of US companies, not in the interests of other countries let alone the interests of our people in the future," says Prof Jane Kelsey of Auckland University.
But the Government says a deal could be a billion-dollar boost for our economy.
"It's going to be big," says Trade Negotiations Minister Tim Groser. "It's going to be significant and it's going to help New Zealanders find well-paid jobs."
An agreement is thought to still be some way off though, despite two years of negotiations.
"For us to get a deal that is acceptable for us, the United States is going to have to give up what's important to some of their politicians -mainly agriculture protectionism and subsidies," says political commentator Matthew Hooten.
"Now that's a big call for the United States."
This latest round of talks will last one-and-a-half weeks, and protestors are planning to voice their concerns the whole time.