Several neighborhood groups in Northwest Washington have urged Metro to speed up the opening of the Tenleytown and Friendship Heights subway stations, fueling renewed debate about plans for extending Red Line service through Northwest into Montgomery County.

"Just about everybody is in favor of the idea of opening the rail earlier," said Steve Posniak, an advisory neighborhood commissioner who represents the Friendship Heights area.

The Tenleytown station is on Wisconsin Avenue NW near Albemarle Street, and the Friendship Heights stop is at Wisconsin and Western avenues near the District of Columbia-Maryland border.

It is not yet clear, however, whether the plan for an accelerated opening of the Friendship Heights station is backed by neighborhood groups in suburban Maryland.

Leaders of the Citizens Coordinating Committee on Friendship Heights, a coalition of Maryland and D.C. groups, have expressed mixed views, citing continued concern among Maryland residents about possible traffic and parking problems.

Under Metro's current plans, rail service would be extended in late 1984 from the Red Line's present terminus at the Van Ness-UDC stop on Connecticut Avenue NW to a new station at Shady Grove in Montgomery County.

The neighborhood groups want Metro to start service to Tenleytown and Friendship Heights in early 1984, several months before the rest of the line opens.

The campaign is viewed by D.C. and Metro officials as a turnabout from stands taken by Friendship Heights groups during the 1970s.

In the past, officials said, most community groups opposed moves to open the Friendship Heights station before service was extended farther into Montgomery County.

The groups contended that the station's opening might lead to increased traffic congestion and shortages of parking spaces in the Friendship Heights area.

The drive for expanded rail service began shortly after Metro and D.C. officials announced a proposal to operate a special shuttle bus during rush hours from Friendship Heights to the Van Ness-UDC station, starting next January. A hearing on the proposal has been scheduled for July 13.

According to District, Montgomery County and Metro officials, no study has yet been conducted of the neighborhood groups' suggestion for extending rail service to Friendship Heights, and officials said the plan raises financial, political and other issues.

No funds to finance an extension of Red Line service have been included in the Metro system's recently adopted budget for the 1984 fiscal year, which starts July 1.

Montgomery County officials are currently weighing other controversial proposals for starting service in mid-1984 on some portion of the new section of the Red Line, perhaps to the Grosvenor or White Flint stations.

Construction of the Red Line from Van Ness-UDC to Shady Grove is expected to be completed by the end of this year or early 1984. The line's opening is scheduled to be delayed, however, because of a shortage of rail cars, now being produced by an Italian manufacturer.

By late 1984, according to Metro officials, a sufficient number of new rail cars is expected to have arrived to permit the extension of service to Shady Grove. Fewer rail cars would be needed to open a shorter section of the line. So service on part of the line might be started sooner, officials said.