High-powered US business organisations have issued a joint statement expressing "deep concern" with the government's decision to introduce plain packaging for tobacco products.
They say it will violate New Zealand's international trade obligations and facilitate illicit trade and counterfeiting.
"Of course we respect the right of New Zealand to regulate in the public interest, but this approach is contrary to regulatory best practices," the organisations said.
"Above all, there is no compelling evidence that it will actually advance the public interest."
The organisations include the US Chamber of Commerce, the National Association of Manufacturers, the Emergency Committee for American Trade, the United States Council for International Business, the National Foreign Trade council, the Transatlantic Business Council and the US-ASEAN Business council.
They say they made a submission to the government last year and want to reiterate those views.
"Although presently this effort is only confined to tobacco products, we see this as a systemic threat to rules which intellectual property and the trading system are dependent upon.
"We hope the New Zealand government will consider the concerns we have raised for the possible impact on New Zealand exports, such as dairy and wine, should other governments feel emboldened to take similar measures."
The government announced on Tuesday it would introduce legislation this year to enforce plain packaging.
It is taking a cautious approach, and before the measure is implemented it will watch developments in Australia.
Plain packaging was introduced in Australia in December and the big tobacco companies lost a lawsuit challenging it.