ENGLish Heritage fears a £290 million leisure and homes complex could end up looking like a factory.

England's leading conservation body has withheld its blessing for international architect Frank Gehry's plans to redevelop the King Alfred centre on Hove seafront pending further reassurances about the design.

Following a meeting with Mr Gehry and developer Karis last month, the organisation accepted the scheme would not compromise Hove's character. But it retained doubts about the external appearance of the proposed residential blocks.

It said it wanted to ensure the blocks resembled a seafront palace rather than a mill or factory and, while it was confident Karis could come up with a supportable scheme, it would reserve its final judgement.

The development, which will go before Brighton and Hove City Council's planning committee in April or May, would provide an indoor sport and swimming centre, 754 homes in two tall towers, and several lower buildings and an art installation by British sculptor Antony Gormley.

Graham Steaggles, historic areas adviser at English Heritage, wrote in a letter to the city council: "We are convinced that the character of this part of Hove can sustain a very localised step-change in scale of the type envisaged.

"While we are not yet able to recommend in favour of the proposals, we are confident that a scheme that we could support is achievable with finite further design development."

An English Heritage spokeswoman added yesterday: "What we don't want to see is an overly plain and uniform facade."

Karis managing director Josh Arghiros said: "We welcome the support of English Heritage and we are encouraged by their advice. Frank Gehry and the design team have spent two years designing this project and we are confident any outstanding issues can be resolved to the satisfaction of English Heritage."

Karis said it was working to provide further information for English Heritage. The developer does not require the body's approval to win planning consent, but such approval might help persuade members of the planning committee the development is appropriate.

Next month Karis will submit a revised environmental impact statement to the city council, including about 20 new computer-generated images, to address outstanding questions on the likely impact of the development on surrounding streets.