The Prince George's County Council voted yesterday to allow the developer of the proposed National Harbor resort in Oxon Hill to build on 13 acres protected by a state preservation act.

The council's action changed the zoning of part of the 534-acre site along the Potomac River--land that under the Chesapeake Bay Critical Area Program had been reserved for agricultural or other open-space uses or for limited development. State law allows the county to rezone a limited number of protected waterfront acres for development.

Council Chairman M.H. Jim Estepp (D-Upper Marlboro) said the 5 to 3 vote in favor of the change represented another show of council support for National Harbor. But the three council members who opposed yesterday's decision said they are concerned that developer Milton V. Peterson wants to build a parking garage on a rezoned tract that is next to a residential area.

"The citizens have real concerns about the parking lot being stuck in their back yard," said council member Isaac J. Gourdine (D-Fort Washington), who voted against the rezoning. "Most of the people turned against National Harbor because of that parking garage."

Andre Gingles, a Calverton real estate lawyer who represents Peterson, confirmed yesterday that the developer will build a garage in the general area of the rezoning. But he said the council members will have final approval over what the garage looks like through a development review process that requires them to approve a detailed site plan for the garage.

That was one of the conditions the council adopted last year when it approved conceptual plans for the resort, which include first-class hotels, a wooded retreat, a waterfront promenade and a gated entertainment venue.

Peterson does not have to submit detailed site plans for the rest of the resort because of a law passed by the council two years ago to speed the approval process for the development.

Plans for the project still need to be approved by the National Capital Planning Commission, a federal agency for the Washington region. The commission is not likely to vote on the project until September or October, according to sources close to the process.

Vladimar Parma, who has lived near the site for 15 years, said yesterday that even if the developer was forced to move the garage, the development is still too dense for an area that adjoins a residential area.

"They are completely ruining my life," Parma said. "It's the traffic. . . . It's the garage. It's everything."