Apparel group Lands' End says it has reached an agreement with labour groups to resolve allegations of anti-union discrimination at a supplier factory in El Salvador.

According to Lands' End spokesman Chris Mordi, the Wisconsin-based company will, under the agreement, monitor the Primo factory for 12 months to ensure it does not infringe on workers' rights to unionise.

In addition, Mordi said, the company will help Primo improve the documentation of its hiring practices.

"Whatever we do, we try to do the right thing and we think this is the right thing," Mordi said.

US-based labour groups including the Fair Labour Association and the Worker Rights Consortium had alleged that some workers at the Primo plant, which makes collegiate clothing for Lands' End, were blacklisted because of their involvement in union activities.

As an extension of the Primo agreement, Lands' End has agreed to supply machinery, cloth and technical assistance of an undisclosed amount to the Just Garments plant in El Salvador.

Just Garments employs many trade unionists, among them workers affected by the alleged discrimination at the Primo plant.

"Lands' End will make a critical contribution to making Just Garments a success and enabling the company to provide secure employment, under good working conditions, " Worker Rights Consortium executive director Scott Nova said in a statement.