Country of origin labelling laws that came into effect in the United States this week could reduce demand for some of New Zealand's beef exports.
The new regulation requires retailers to display the country of origin for a range of food products, including beef cuts, ground beef, lamb and other meats, fish, fruit and vegetables.
The United States is New Zealand's biggest export beef market. Up to 90% of the beef sent to the US is manufacturing beef which is blended with American product for the hamburger and ground beef trade.
Meat and Wool New Zealand's Washington-based regional manager for North America, Kelvin Whall, says the new labelling rules do not affect the food service sector and beef used in hamburgers.
The rules do apply to ground or minced beef sold in stores and supermarkets.
He says a number of retailers have already stated reluctance to use ground beef that does not originate from North America and have reduced their use of imported beef.
Mr Whall says later in the year, when North American supplies run down, the situation may change.
He says the labelling law does not affect lamb exports to the US because they are already branded and marketed as New Zealand products.
The horticulture industry body, Horticulture New Zealand, does not think the rule change will create any problems for its exporters.
Communications manager Leigh Catley says most fruit and vegetables already carry a "produce of New Zealand" label, and the produce attracts a premium.