President Reagan's ambitious new federal land sales program--which his budget says will generate $13 billion in revenue over five years starting in fiscal 1983--is in trouble.

It is under fire from environmentalists, congressmen suspicious of government intrusion into states' rights and bureaucrats who say they can't sell land they don't have.

Roy Markon, commissioner of the General Service Administration's Federal Property Resource Service, said, "We can't control the success of this program. The ability to sell will depend on market conditions and the suitability of the property."

The GSA currently would like to sell 498 parcels of federal excess property valued at almost $1.3 billion. However, 186 parcels have been on the market for more than two years, and some are clearly unwanted. Nonetheless, the Reagan budget shows that $1 billion will be raised from property sales in fiscal 1983 and $4 billion in each of the years following. Last year, the GSA disposed of only $50.3 million worth of real estate valued at $139.6 million.

GSA is supposed to generate half of the revenues with the rest coming from lands disposed by the Bureau of Land Managment, the Forest Service and the Army Corps of Engineers. In total, 27 land-owning federal agencies are expected to put property up for disposal.

A new White House working group, the Property Review Board, is supposed to cut through the morass and prompt agencies to put up an annual quota of land.

At a House Government Affairs subcommittee hearing yesterday, Rep. John L. Burton (D-Calif.) said the administration's revenue "figures are highly inflated" because they do not take into account restrictive local zoning of a federal parcel when sales figures were computed.