CABE has objected to Urban Splash's plans for a large residential scheme on the seafront at Morecambe.
The FLACQ-designed project would create a "dominating mega-block" and threaten permeability from the town to the sea, the watchdog said.
Urban Splash plans 533 residential units, alongside shops and cafes.
The developer said in a statement: "We are meeting with Lancaster City Council to review the statutory consultees' comments and hope to address any relevant issues including CABE's comments shortly."
CABE did have praise for the curved form of the design and also decided not to object to the proposed demolition of the listed wall around the renovated Midland Hotel, reopened by the developer in the past year. Local objectors have threatened to chain themselves to the wall to prevent demolition.