Fairtrade is planning to introduce a standard for manufactured goods that will ensure a better price for factory workers.
At present, the Fairtrade mark is awarded to goods such as bananas and coffee beans produced using methods that guarantee a better deal to farmers in developing countries.
In November last year, Fairtrade extended its range of products to include cotton, partly in response to the demand for ethical clothing.
TopShop has latched on to the trend and is stocking items from ethical clothing companies People Tree, Gossypium and HUG. Although such organisations may describe themselves as "ethical", there is no recognised authority to decide if they really are.
The new Fairtrade standard, which is in the early stages of development, seeks to address the anomaly.
Diana Gayle, product manager for cotton at the Fairtrade Foundation, said: "Workers in develo-ping countries deserve a better deal."