High-profile fashion retailer Topshop Australia has collapsed under debts and entered voluntary administration, with the future of its stores and workers under a cloud.

Administrator James Stewart, of Ferrier Hodgson, said the company would continue to trade as normal while it considered its "optimal operating structure".

"It will be business as usual as the administrators work closely with Arcadia Group (the UK owners of the Topshop/Topman brand) on supporting and right-sizing the Australian business to a sustainable platform going forward," he said.

"Topshop/Topman is one of the world's best known fast fashion retailers operating nine stand-alone stores, 17 Myer concessions and an online business in Australia."