The search for designers to revamp two 'gateway locations' in the capital will coincide with this June's London Architecture Biennale.
The local authority has stipulated it wants 'innovative, striking buildings' that incorporate 'some WC provision' at the sites, with the winning practice picking up £5,000.
One site is at the eastern end of Tooley Street, the other on Tower Bridge Road, close to Caledonian Road Antiques Market.
A judging panel will select winners after the deadline of Friday 5 May 2006. Two commended schemes will each be awarded a prize of £2,000.
A Southwark Council spokesperson said it is 'hoping that both designs will add something of interest to the urban fabric at these prominent and prime gateway locations,' and that 'they are sustainable in every sense of the word'.
For more information visit www.southwark.gov.uk/ideascompetition