Business and export groups have come out in support of the Trans-Pacific Partnership (TPP), ahead of its formal signing in Auckland on Thursday.
They've written to Prime Minister John Key saying they believe economic growth would be under threat if New Zealand wasn't part of the 12-nation free trade agreement.
BusinessNZ says the groups represent most of the private sector.
"Business understands that being part of TPP will enable more competitiveness, higher exports, higher value jobs and new technology and practices," chief executive Kirk Hope said today.
"New Zealand companies will gain more opportunities for profitable trade and New Zealanders' wealth will grow."
Mr Hope said no agreement was perfect, but the TPP had achieved "enormous gains for New Zealand without the need for significant policy change".
Signatories to the letter to Mr Key include BusinessNZ, ExportNZ, Federated Farmers, dairy, meat and forestry industry representatives, and the Auckland, Christchurch and Wellington chambers of commerce.
Mr Key said in his State of the Nation speech last week it would be "inconceivable" for New Zealand to exclude itself from the TPP.
The Labour Party is opposing the agreement in its current form.
It believes the TPP will allow multi-national companies and other countries to interfere with the Government's ability to pass laws in New Zealand's interests.
The TPP partners are New Zealand, Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, Peru, Singapore, the United States and Vietnam.
Meanwhile, a major anti-TPP protest will be held in Auckland on Thursday before the ceremonial signing of the deal.
Advocacy group Auckland Action Against Poverty will be among the groups supporting the protest.
"We will encourage members and supporters to participate in either, or both, the Real Choice blockade protest gathering at 9am in Aotea Square and the It's Our Future march which starts at midday from the same location," spokeswoman Sue Bradford said.
"Even though its purpose is largely symbolic, Thursday's international signing of the TPP is a highly significant event.
"This is an opportunity for all of us who seek to defend our country's economic and political sovereignty to come together and take a stand."
Ms Bradford says while the TPP "might be good for the powerful and rich", it won't mean anything for the unemployed, beneficiaries, students and low-wage workers.
She believes the agreement will be bad for New Zealand and its ability to make laws about its own future.
Newshub. / NZN