Clothing maker American Apparel is stepping up its partnership with online retailer Asos as it tries to build new distribution and sales channels for its basic fashions.

The expansion with UK-based Asos, which has more than 3.7m members, follows a 100% sell-through rate of a test buy earlier this year, American Apparel said today (8 August).

The Los Angeles-based company, which is struggling to reverse falling sales, recently teamed up with eBay to open its first online lifestyle shop.

Asos will be key here thanks to its popularity in Denmark, Russia, New Zealand, Singapore and Hong Kong - countries where American Apparel does not have stores.

"This is a partnership that leverages their strengths as an online platform and ours as a manufacturer and global brand. We're going to grow our businesses together," said American Apparel CEO and founder Dov Charney.

Product categories currently offered are men's, women's, swim and accessories. Footwear will be added in 2012. Inventory is purchased directly by Asos through American Apparel's wholesale business, and is then displayed and marketed through Asos's online platform.

The online retailer booked a 63% rise in revenues for the first quarter of this year and international sales now account for over half (57%) of its retail sales mix.