Hart wrote on Twitter that he was looking for an agency to build 'something special' for the online retailer.
It is unlikely that Hart's requests will affect the online retailer's arrangement with advertising agency Mother, which it appointed in January. The agency was appointed as the brand's first agency and won the account without a pitch. It handles Asos' print, outdoor, online and TV communications. The activity was previously handled in house.
Last month Asos appointed former consultant at Mother, Clare Dobbie, as its marketing director. Reporting to chief executive Nick Robertson, Dobbie, who takes up her post in March, will also be a member of the Asos.com operating board.
The online retailer, which is estimated to have 5.2 million unique visitors a month, is one of the fastest growing internet fashion outlets. It reported record sales last year, with total sales soaring 47% for the six months to September 2009.