Prince George's County planners have completed a development plan for the southwestern part of the county that calls for a building boom in one of the last close-in suburban areas that remains substantially rural.

Development along the Indian Head Highway and Branch Avenue corridors in Prince George's has been choken in recent years by the lack of suitable roads and sewer lines and by citizen opposition to major building projects. As a result, nearly 41 percent of the 45-square mile area is undeveloped.

The new plan calls for the construction of a "southeast expressway" from the Beltway to the southern end of the county, the extension of Interstate Rte. 295 beyond the Beltway, and the expansion of both Indian Head Highway and Branch Avenue.

These roads and the construction of the planned Metrorail line to Rosecroft Raceway would, according to the plans, lead to the construction of 30,000 new homes and a regional commercial center, including hotels and office buildings, along the Potomac River.

The plan recommends, however, that new housing developments in the area be frozen until at least some of the new road construction is complete.

The plan, which must be approved by the County Planning Board and the County Council, is likely to face vehement opposition from area residents and politicians, who are opposed to both new highways and new homes in the area.

"The only people who could conceive of this thing could be planners," Del. Charles Blumenthal said yesterday. "It's planning for massive future development that we do not want or need."

"It's going to turn my district into a concrete apron of highways," said state Sen. Peter Bozick.

Prince George's planning officials insist that development southeast of the District line is inevitable. "This is an area where there are only two major roads, and both already have unacceptable congestion levels," said Albert Wang, who supervised the plan's drafting.

"Development in this area is inevitable. This plan proposes the minimum in roads that will be required to accommodate the growth."

Planning officials also contend that the new plan substantially lightens the density of development proposed for southern Prince George's in the current scheme for the area, which was adopted in 1963.

If the new development map is approved by the county council, all zoning in the area -- which is roughly bounded by the District line, the Suitland Parkway, the Potomac, and Old Fort and Allentown roads -- will be changed to allow the new highways and building projects.

There are no time limits attached to the development. Rather, according to the plan, each new phase of building will be triggered by the completion or expansion of roads.

The improvements will be quite expensive. The plan recommends the construction of a senior high school, five junior high schools, 13 elementary schools, a library and parks to accommodate a population growth of 70,000 to 95,000.

Blumenthal estimated yesterday that the proposed new highways, roads, and road expansion alone could cost $2 billion.

"There are about 1,000 people who could be displaced whtn the roads are built," Blumenthal said. "The only people who want that are people who don't live in the area -- like developers. It's more important to preserve some of the agricultural areas that are left in Prince George's."

Another major obstacle for eventual development in areas south of the Beltway may be limited sewage treatment capacity. Development so far has been stymied by limited access to sewage treatment plants at Piscataway and in the Mattawoman Basin on the Charles County line.

The Prince George's planning board will hold two public hearings on the development map on November 8 and 15, and will solicit comments from Prince George's Executive Lawrence Hogan before voting on the plan.