Developer Crescent Heights will unveil proposed designs Thursday for a large outlet mall and residential complex that could drastically alter the entryway into South Beach.

Three firms competing for a contract to design the project around the site of the abandoned South Shore Hospital just north of the MacArthur Causeway will present their visions at Miami Beach City Hall’s commission chambers — an unprecedented venue for a private event.

“We look at it as a community event and community opportunity,” said Russell Galbut, Crescent Heights’ managing principal.

In past years, the three-block project stretching north from Fifth Street and Alton Road has been discussed as a high-end shopping center.

But Galbut said Crescent Heights now plans a mall with new retail partner Paragon Outlets. Plans include public components, such as a three-acre park and a strategy to improve the severely congested intersection where Alton Road meets the causeway.

Among the solutions discussed: building a new northbound Alton Road flyover with an extra lane.

Gensler, Benoy + Add, and Skidmore, Owings and Merrill have been tasked with designing a winning plan.

At roughly 450,000 square feet of retail space, and another 200,000 square feet of condo space, the project could have long-term implications for traffic flow, city shopping and the view tourists have when they head into the city’s entertainment district from the causeway.

Galbut and the city have talked in the past about hiring a prominent architect to design an iconic pedestrian bridge over the highway in order to connect the bay walk. He and Commissioner Jonah Wolfson flew to New York several months ago to meet with an architect and discuss the idea.

“The project we’re talking about here is probably one of the largest we’ve considered in a long, long time,” Commissioner Jerry Libbin said before a unanimous April 11 vote to allow Crescent Heights to use the city’s commission chambers for its presentation.

That decision, however, hasn’t been wholeheartedly supported by the community.

Some activists questioned commissioners’ decision to allow Galbut and company to use a public space for a private project, which City Clerk Robert Parcher said was unusual and could set a precedent.

City Hall has “never been used for purely private promotion,” said activist Frank Del Vecchio.

But Galbut said Crescent Heights’ offer to invest in public infrastructure goes beyond “private” investment.

He also said Crescent Heights hopes to learn which design the community supports, and boasted in an email to Del Vecchio about the jobs Crescent Heights will create through the project.

“Our project will create over 1,900 construction jobs and provide permanent employment for over 1,800 individuals once our doors open,” he wrote. “This will create the second largest employer on Miami Beach, and well over 400 of those jobs will be management positions paying between $75,000 and $100,000 per year with full benefits.”

It’s unclear if Crescent Heights will pay rent to use the commission chambers.

Crescent Heights’ project will ultimately need commission approval.

Galbut says if the community or commission reject the plan, Crescent Heights will build a residential project.

“If we don’t get full cooperation and see a desire to move forward then we’ll back away, build a residential community within our rights and say ‘thank you very much,’ and we’ll go home.”