Trade groups from 25 countries in Africa, South America, Central America and North America have issued a joint appeal to the US government to proceed cautiously in textile talks concerning the Trans Pacific Partnership (TPP) trade pact.

Claiming that nearly $30bn in existing textile and apparel trade and over 2m workers could be put at risk by an unbalanced agreement, they are calling for a final agreement to include a yarn forward rule of origin, strengthened customs rules and special mechanisms to deal with state owned companies and state subsidised companies.

In a letter sent last week to US Trade Representative Ron Kirk, the groups argue that "a yarn forward rule will help to ensure that third parties, such as China, do not take advantage of the agreement."

They also note that Vietnam, a TPP participant, is already the second largest exporter of apparel of the United States, most of that made with Chinese yarns and fabrics. And they raise issue with the government of Vietnam's historic support of its textile sector, including the use of subsidies and ownership of large state-owned companies.

"Even with paying full duties, at $6.3bn, Vietnam is already the second largest exporter of apparel to the United States," the letter says. "It is also one of the fastest growing exporters and has doubled its exports to the United States during the last five years.

"We are particularly concerned that Vietnam, using primarily Chinese yarns and fabrics, exports the same type of apparel that our sectors make and send to the United States every day."

The trade associations believe a yarn forward rule "will help to ensure that third parties, such as China, do not take advantage of the agreement.

"Strengthened customs enforcement rules will also be essential in a final agreement. Finally, we also urge you to include special mechanisms in the agreement to help counter-balance Vietnam's historic support for its textile sector."

The joint letter was signed by the African Cotton and Textile Industries Federation (ACTIF); Association Des Industries d'Haiti (ADIH); Camara de la Cadena Algodon, Fibras, Textile y Confecciones, Associaion Nacional de Empresarios de Colombia (ANDI); the Central America-Dominican Republic Apparel and Textile Council (CECATEC); the National Council of Textile Organizations (NCTO); and the Comite Textil Sociedad Nacional de Industrias de Peru (SNI).

Separately, a group of US lawmakers is calling on trade officials to ensure that ongoing talks on the Trans Pacific Partnership (TPP) do not lead to lower duties on US footwear imports.