The Federal Trade Commission has dismissed its charges that a major real estate company had illegally required buyers of its Florida condominiums to take long-term leases on recreation facilities.

"This case should no longer be pursued," the FTC said of the case, it began in 1976 against developers of the Century 21 Commodore Plaza development in Dade County, Fla.

The commission said owners of condominiums settled their complaints against the developers by buying the recreation lease after the case began.

Since the practices that led to the case are no longer under the control of the developers, an FTC order "could verge on being frivolous," the commission said.

In addition, the commission said new Florida laws do not go as far as an FTC order in the case could have gone, but "may act as a substantial deterrent to the practices that we expressed concern about in our complaint.

"Because the laws are relatively new, we have no way of determining whether their operation will be an effective means of consumer protection or whether consumers are still being injured despite the existence of the laws. o

"Out of deference to state actions and because it is impossible, at this point, to gauge the public interest, we feel that the prudent course is to stay commission action for the present," it said.

The FTC decision follows the substance of an initial decision in February by Administrative Law Judge Lewis F. Parker and the recommendation of the FTC staff. However, the commission strongly chastized Parker for dismissing the commission's charges of advertising misrepresentations, saying the FTC alone has that authority.

"Dismissal of these charges was warranted, although the procedure followed was incorrect," the FTC said.