It is a deal shrouded in so much secrecy that a politician with top-level United States security clearance was barred from viewing the draft text.
Trans Pacific Partnership negotiators roll into Auckland next week for the 15th round of talks on the trade pact.
But the deal-making will take place behind closed doors - and critics are raising concerns about what New Zealand is signing up to.
US Senate finance subcommittee on trade chairman Ron Wyden also sits on the committee that oversees America's intelligence agencies. But he was banned from seeing a draft version - and only after protest was permitted to read it in a secure room.
Yet more than 600 representatives of pharmaceutical and film corporations are given access because they are deemed to be US Government ''advisers''.
Last week Prime Minister John Key met six other TPP leaders and said President Barack Obama was determined to get the deal sewn up by next year.
But visiting US trade lawyer and activist Lori Wallach said the pact was becoming increasingly controversial in the US, as concern built about consequences of the North America Free Trade Agreement, which effectively allows private companies to sue governments over laws they believe infringe their future profits.
Critics believe the TPP will open up signatories like New Zealand to litigation from major offshore companies.
The recent US election campaign saw a wave of ads focused on offshoring jobs and challenges to sovereignty. Ms Wallach said President Barack Obama had no authority to ''fast-track'' negotiations, which any concessions must be voted on by Congress. ''It's a little bit of a problem for him ... if he starts a national debate about trade authority for TPP he is going to have a close scrutiny of the agreement, which will not go well,'' she said.
Ms Wallach said the secrecy was unprecedented and put Mr Wyden, a free trade champion, ''on the warpath''.
Professor Jane Kelsey, of Auckland University, said there were also domestic political barriers. Even if a deal was signed by the forecast deadline of October 2013, select committee scrutiny and any necessary legislative changes were not likely to be completed by the 2014 election. The Greens, Mana and NZ First are opposed to the TPP and Labour recently passed a remit outlining caveats which would reject many aspects. This means a coalition on the left could veto the deal.
Green party co-leader Metiria Turei has launched the Profiting from Injustice report showing how law firms are cashing in on disputes over trade agreements. ''Governments around the world are paying out huge sums after losing decisions decided by unelected officials behind closed doors,'' she said. The Australian Government has refused to sign up to investor state dispute clauses in the TPP - and New Zealand should follow suit, she said.
The experts will attend a TPP symposium today at Victoria University.
- © Fairfax NZ News
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