Marks & Spencer, Topshop, Sainsbury's and New Look are among the retailers squaring up to battle for the ethical pound this year.
M&S is building on its recent 100-point eco plan with the launch of a range of fair trade cotton separates, from shirts to socks, for men, women and kids.
It launched 11 Fairtrade-certified items last year. However, the expansion to 67 products, which will be introduced in time for Fairtrade Fortnight on February 26, represents the biggest fair-trade fashion offer on the high street.
The range will include jeans, sweatshirts, polo shirts, formal shirts, knitwear, pyjamas and underwear. Prices will range from £4 for two pairs of socks to £29.50 for women's jeans.
Sainsbury's is also introducing a casualwear range for Fairtrade Fortnight. The 22-strong collection, which will be priced between £5 and £18, will initially be sold in 55 stores. Sainsbury's eventually intends to roll out the range to the 250 branches that stock its Tu clothing offer.
Topshop is extending its relationship with fair-trade fashion brand People Tree by launching a capsule collection into 20 stores. The People Tree for Topshop range, which is both organic and fair trade, features tunics, bubble-hem tops and racer-cut vests.
People Tree founder Safia Minney said Topshop had to commit to the collection last spring so the cotton order could be fulfilled.
New Look and Monsoon are also expanding their ethical offers in March, with the latter rolling out a T-shirt collection. New Look will put its organic range into 150 stores.
Smaller retailers and brands, such as Gossypium, Ascension and Hug are also backing Fairtrade Fortnight, while ethical clothing retailer Bishopston Trading, which has five stores in the west of England, is expanding its fair-trade collection for next season.