The Sheraton Bal Harbour, a nearly 5-decade-old beachfront resort formerly called the Americana that once ranked among South Florida's premier tourist destinations, is set to be demolished next year to make way for condominiums and a condo-hotel.

Developer Jorge Perez said he is paying ''in excess of $200 million'' to develop the property in a joint venture with Starwood Hotels and Resorts, which owns the Sheraton Bal Harbour. They plan to build a 350-unit condominium building and a 250-room ultra-luxury St. Regis condo-hotel.

It may be the first demolition of a South Florida building designed by famed architect Morris Lapidus, said historian Paul George and Miami Beach architecture author Randall Robinson. The Sheraton Bal Harbour will stay open until May 2006, said Perez, chairman of Miami-based Related Group of Florida.

The move is yet another remake of a high-profile South Florida hotel property amid the region's ongoing real estate boom. Some worry the changes are eroding the area's stock of hotel rooms -- the latest a favorite of America's labor unions.

Perez, the state's most prolific high-rise condo developer in the past dozen years, also said the project amounts to his final local high-rise condominium project -- at least for now.

''This is it for us in South Florida,'' said Perez, whose first high-rise condo was South Beach's Portofino Towers in 1992. He has nearly 40 condo projects underway from West Palm Beach to downtown Miami, much more than any other developer in South Florida. He said demand for condos remains strong, but prices for new land have become too expensive.

''We need to concentrate on what we have on our plate right now,'' said Perez, who also has condo projects in Fort Myers and Las Vegas.

Starwood Hotels and Resorts declined to comment. The White Plains, N.Y.-based hotelier, which is publicly held, owns such brands as Sheraton, W Hotels and St. Regis.

In addition to the condo tower and condo-hotel, the new development is to include a 6,000-square-foot ballroom, a spa and two restaurants.

The 8.8-acre site has long been admired because it sits on the beach and is across from the Bal Harbour Shops.

Designed by Lapidus and built by the Tisch family in the late 1950s, the 645-room Sheraton Bal Harbour once was one of the most glamorous resorts in South Florida. First known as the Americana hotel, it was renamed the Sheraton Bal Harbour in 1980.

The hotel is not protected by a historic designation, and Related is not expecting opposition from preservationists.

But some observers expressed disappointment. ''It is a crying shame,'' said historian George. ``It was one of his greatest buildings in the area.''

Lapidus' other designs include the Eden Roc and Fontainebleau hotels in Miami Beach.

HOTEL ROOM CONCERNS

The announcement also comes amid concerns that South Florida's booming condominium market will endanger its hotel stock. The 585-room Roney Palace on Miami Beach has been converted to a condominium, and three months ago Related said it would demolish Miami's 598-room Sheraton Biscayne Bay for a residential complex.

Developers plan demolition or renovations at the Sonesta in Key Biscayne; the Yankee Trader and Clipper in Fort Lauderdale; and Miami Beach's Shore Club, Fontainebleau and Holiday Inn.

Meanwhile, hotels across South Florida are selling rooms individually as condo-hotel units, which critics say will turn off large groups needing to book years in advance. Renovation plans also create the potential for short-term inventory crunches.

''I'm concerned next year when 2,000 rooms disappear,'' said Stuart Blumberg, president of the Greater Miami & The Beaches Hotel Association.

The Sheraton Bal Harbour was slated as one of two team hotels for the 2007 Super Bowl, and local tourism officials recently notified National Football League executives of Related's plans.

William Talbert, head of the Greater Miami Convention & Visitors Bureau, which is coordinating South Florida's Super Bowl preparations, said another oceanfront Miami Beach hotel will be picked as a team headquarters.

And with the St. Regis, South Florida will get a more upscale hotel, he said. ``Remember, the five-star product we have attracts and keeps the Art Basels of the world, is very attractive to the Microsofts of the world.''

UNION HOTELS

The demolition also means the loss of one of South Florida's few large unionized hotels. Labor groups and their allies -- including Democratic presidential candidate John Kerry -- regularly stayed at the Sheraton Bal Harbour.

Perez shrugged off any concerns.

``This and the Sheraton Biscayne Bay project are going to be our jewels in South Florida.''