Neighbours say plans to build 400 homes alongside a revamped seafront leisure centre will create a "high-rise hell".
Brighton and Hove City Council approved plans for a £23 million redevelopment of the King Alfred Leisure Centre in Hove last month.
Work to bring the run-down centre up to scratch will be partly financed by the homes.
Plans for the site will be unveiled next week but Labour councillor Simon Battle is trying to galvanise local feeling in advance of the meeting.
He said: "The proposals will devastate Hove seafront. It will be high-rise hell for residents.
"The buildings will need to be many storeys high to squeeze in the number of flats required.
"Sussex Heights in Brighton contains 115 flats and at 82m is the tallest residential building in Brighton.
"Think about nearly four buildings the size of Sussex Heights, or five Embassy Courts, and you can get a feel for what could be in store for the King Alfred site."
The council decided to go ahead with the redevelopment after a survey showed 80 per cent of local people were in favour of improvements.
The survey did not give voters the opportunity to back a proposal for a lesser renovation, with a smaller-scale housing development.
Coun Battle said: "People in central Hove want a new leisure centre but not at any cost."
A spokesman for the council said: "This analysis presumes flats would be the same size as those in Sussex Heights or Embassy Court. This is not the case.
"Any building would be about the height of surrounding ones.
"What the site might look like will become clearer in a planning brief we are publishing for public comments within the next week.
"There are lots of people in the city without decent homes and that needs taking seriously."
Coun Battle is urging residents to write to the council during a forthcoming six-week consultation period, objecting to the plans.
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