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The lack of clarity over dairy, New Zealand's biggest export commodity, "will change because it has to change," Groser said. If dairy was excluded from the TPP, New Zealand would walk away, he said.
The TPP agreement seeks a trade agreement spanning the Pacific Rim and currently involves 12 countries: New Zealand, Australia, the United States, Canada, Japan, Singapore, Malaysia, Brunei, Vietnam, Chile, Peru, and Mexico.
Where the deal differs from other free-trade agreements is that it includes alignment of regulatory settings across borders rather than simply removing quotas and tariffs. It has faced staunch opposition from those who claim it undermines national sovereignty through investor-state dispute settlement (ISDS) provisions and through its treatment of intellectual property and medical procurement.
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Groser again defended New Zealand's negotiating position, saying he wouldn't "sign up to poorly constructed ISDS provisions that 'transfer control of the country's sovereignty' to foreign corporations" or "undermine a central pillar of our public health system - the pharmaceutical agency called Pharmac" or prevent future governments from implementing well-designed environmental protections.
"If and when we get TPP in place, extreme claims that the sky is going to fall in will be made, irrespective of a balanced and sober reading of the final agreed TPP texts," he said.
Groser also scotched speculation that the agreement was part of the US's plan to contain the emerging Chinese superpower, and said China could potentially sign up to a later iteration of the TPP.