Metro officials yesterday recommended narrowing the number of proposals under consideration for a long-delayed section of the Green Line subway between Anacostia and southern Prince George's County.

In six weeks, the transit authority's board of directors is scheduled to vote on a route for the controversial rail line.

Some Prince George's residents have pressed for a route with a terminus near Branch Avenue, while others have advocated a terminus near the Rosecroft Raceway.

In outlining their recommendations yesterday, Metro planning officials said that both the Branch Avenue and Rosecroft Raceway routes appeared acceptable.

"None of the alternatives can generate a clear or significant advantage," said Albert J. Roohr, a senior Metro planner.

Roohr urged the Metro board to consider three possible routes linking the planned Anacostia station near the Anacostia Freeway (I-295) and Howard Road SE with southern Prince George's. He recommended dropping two other proposals.

One of the routes recommended by Metro planning officials would terminate at Rosecroft Raceway, while two other routes would extend to Branch Avenue.

The principal difference between the two Branch Avenue plans is that one route would include an Alabama Avenue station near Suitland Parkway, while the other would include stations in Congress Heights and at Southern Avenue.

District officials long have favored the Congress Heights and Southern Avenue stations. They have argued, in part, that these stations would serve St. Elizabeths and Greater Southeast Community hospitals.

Roohr recommended setting aside two other Branch Avenue proposals that included fewer stations. He said the additional stations would be needed to provide parking facilities and bus connections and to serve residential areas.

Construction of the Green Line in southern Prince George's has been blocked for more than two years by a federal judge's order. The court dispute was triggered by a 1980 decision by the Metro board to shift the route's terminus to Rosecroft Raceway.

The move was contested by county residents and business operators who supported Metro's earlier plan for a Branch Avenue terminus.

The County Council and other Prince George's officials recently endorsed the Branch Avenue plan.

Last summer, U.S. District Court Judge Norman P. Ramsey modified his March 1982 order to clear the way for construction of the Green Line between the Waterfront station at Fourth and M streets SW and the Anacostia stop.

Officials plan to ask Ramsey to approve a route between Anacostia and southern Prince George's after the Metro board votes next month.