A visit by US officials could be used to pressure the government into further concessions on the Trans Pacific Partnership deal, a long time critic of the trade pact says.
The US team will meet officials from the Ministry of Foreign Affairs and Trade in the next week or so to look at how New Zealand will put its obligations under the Trans Pacific Partnership (TPP) into practice.
TPP critic and Auckland University law professor Jane Kelsey said the Americans were trying to bully the government into getting what they wanted.
"It's outrageous that the US government is sending people down to New Zealand to monitor how we're implementing the TPP agreement.
"The US is quite notorious for doing this and notorious for putting enormous pressure on governments to do more than they think they need to do to satisfy the US demands."
US political support for TPP is in short supply, with the leading presidential hopefuls for the Democrats and Republicans against it.
Some American politicians are demanding changes for their support, including beefing up the monopoly protection period for the next generation drugs, biologics, from five to 12 years.
Professor Kelsey feared American officials will put pressure on New Zealand to buckle.
"We need to know that the government is going to draw a firm red line, and say it will not make any movement even if it means that the US plays hardball and says the TPPA then won't come into force."
Professor Kelsey wants the government to fully disclose what the Americans want, and New Zealand's response to them.
TPP not open to renegotiation - McClay
Trade Minister Todd McClay said there was nothing sinister about the US sending a team here, and he was not expecting them to strong-arm his officials.
"We can meet all of our obligations in the draft legislation that will be put before Parliament. That's an issue for the New Zealand parliament and no other country.
"Just as the process that's underway in the other countries is for their parliaments to consider, not the New Zealand government."
The visit also provided an opportunity for New Zealand to find out where the ratification process was up to in the US, he said.
Mr McClay would also be holding ratification talks with a number of TPP countries while in Peru for an APEC meeting next month.
He reiterated the TPP was done and dusted, and was not open to any renegotiation.
"If we need to renegotiate, there is a long list of things I might want to look at as well."
Stephen Jacobi, executive director of the International Business Forum, a TPP proponent, is also relaxed about the Americans' visit.
"One can't help thinking they might be better spending their time in the US working on the ratification. But if it helps to demonstrate to the US audience that the business of TPP, and getting on with it, is going on despite this rather fractious election campaign, then so much the better."
Mr Jacobi pointed out the US was also sending teams to developing countries in the agreement, such as Vietnam, to provide the expertise that they needed to boost laws on labour and environmental standards, which should be supported here.
"In the case of Vietnam, not only do they have to change their intellectual property (IP) laws, they also have to change their laws around labour rights. They're having to advance quite a lot of legislation around meeting core labour standards."
"I'm just waiting for the Council of Trade Unions (CTU) and the Labour Party to issue press releases heralding this development. But I'm not holding my breath for it."