The scheme, which will straddle the Leeds-Liverpool canal ( pictured), is being backed by the housing-market-renewal division of Sefton Metropolitan Borough Council.
The RIBA Competitions Office is inviting entries from architects, engineers and students for the first stage, which will be judged anonymously.
The winner will be picked from a shortlist of six, who will be interviewed to discuss their submissions. The submission deadline is 10 January next year.
For further information contact the RIBA Competitions Office on 0113 234 1335 or visit www. ribacompetitions.com