US Trade Representative Ron Kirk has rejected calls by American lawmakers for dairy to be excluded from a free trade deal that includes New Zealand.
The legislators want Mr Kirk to exclude dairy from the eight-country Trans Pacific Partnership.
The call from the Congressional dairy farmers caucus followed a letter from 30 senators in March opposing dairy's inclusion.
It claims increased imports of New Zealand dairy products will depress already-low prices and devastate the US industry.
But Mr Kirk says it is too early to exclude sectors from a possible deal and improving access to overseas markets as a result of the deal could be a boost for American farmers.
Meanwhile, New Zealand Prime Minister John Key has expressed unease at the inclusion of Canada in the Trans Pacific Partnership.
Canada, which has a strong local dairy lobby, is not currently part of the talks but is believed to be pressing to join.
