The European Union's restrictions on wine labeling was being criticized by the United States, saying they hinder US wine exports to the 27-nation bloc.
The US Trade Representative's office said the EU's policy of seeking exclusive use of so-called traditional terms such as tawny, ruby, reserve, classic, and chateau on wine labels had an undesirable effect.
"The EU's regulation of traditional terms severely restricts the ability of non-EU wine producers to use common or descriptive and commercially valuable terms to describe their products sold in the EU," the USTR said in a report on trade barriers.
According to the report, the EU may allow third-country producers to use the traditional terms if their governments forge an agreement with the EU regulating use of the terms in their markets.
While no US shipments have been blocked to the EU, the USTR said, "US industry reports that the regulation has deterred exporters from seeking to enter the EU market."
The report came as the US and the EU prepared to begin negotiations this year on an ambitious trade and investment partnership that would create the world's largest free-trade area.
The USTR said it was "problematic" that the EU was trying to expand the list of the so-called traditional terms to include additional "commercially valuable terms" that lack a common definition across all EU member states.
Noting that the EU maintained its policy is aimed at avoiding the misuse of terms that may confuse customers, the US trade office said the terms have been used "without incident" on US wines in the EU market for many years.
The EU had allowed the use of the terms by other countries, including Chile, South Africa, Canada, and Australia, it said.
According to the USTR, the US this year will continue to work with US wine exporters on how to resolve the wine labeling issues with EU officials at the World Trade Organization and in bilateral meetings.