Walt Disney World is funding much of the opposition to the casino bill, with its advocates warning more gambling would tarnish Florida’s appeal as a family vacation spot. But supporters of the casino industry say Miami’s potential as a convention powerhouse could be the main motivator.

“You add gaming in with everything else, you’ve got the No. 1 convention destination,’’ said Glenn Schaeffer, a former Mandalay Bay president in Vegas who briefly worked for the Fontainebleau Miami Beach. “Orlando would have to up its game.”

Broward’s tourism industry hasn’t rebounded as strongly as in Miami-Dade, where a steady stream of foreign tourists bolstered bookings throughout the downturn. Casino companies are also shopping potential Broward sites, though industry insiders say Miami is the No. 1 choice for a casino resort given its global appeal.

Genting estimates its 5,200-room Resorts World Miami would employ 19,000 people. That would make it Miami-Dade’s largest private employer. Under current conditions, that many jobs would shrink the county’s unemployment rate from 10.2 percent to 8.8 percent.

With 30 acres and six towers modeled after a coral reef, Resorts World Miami would be grand enough to become a destination unto itself, Genting contends. Executives pointed to a similar Genting resort in Singapore, saying it helped boost tourism in the country by 40 percent. A top target would be Latin American gamblers who switch planes in Miami on their way to Vegas.

Genting’s plan calls for a sprawling 200,000-square-foot meeting space on an upper floor of its resort. Sands said it would create an exhibit hall with as much as one million square feet of space. — about twice the size of the Miami Beach expo. Sands, which runs one of the top convention centers in Vegas, claims it can bring the kind of large-scale meetings and trade shows that have mostly eluded Miami Beach and its 1957 convention center.

“There are lot of cities that are a lot less appealing than Miami that do better with conventions and trade shows,’’ said Andy Abboud, vice president of government relations for Sands. With fewer than 2,000 rooms, a Sands downtown resort would not be large enough to accommodate the thousands of attendees for major shows, so local hotels will benefit, he said. “We don’t want to build it all.’’

A downtown convention center may be successful enough to leave Miami Beach wondering if it needs one too. A Sands facility large enough to house the Miami International Boat Show and other massive events, would be a significant threat, said Stuart Blumberg, a co-chair of an advisory panel for the Miami Beach Convention Center. “The Sands model would really build up the downtown hoteliers,’’ he said. “It puts the Beach [center] out of business.”