An official advisory panel recommended yesterday that the hourly wage for domestic workers in the District of Columbia be raised to at least $3.50 an hour - the highest government-set minimum wage for any group of workers in the United States.

If approved, which seems likely, the proposal would give a pay increase of up to 85 cents an hour to an estimated 9,000 maids, housekeepers, companions to the aged and full-time baby sitters, a class that traditionally has been near the bottom of the economic ladder.

The recommendation was made by a nine-member fact-finding panel to the D.C. Minimum Wage and Industrial Safety Board, which will reach a decision after holding a public hearing in August.

Domestic workers in Washington are now paid a minimum of $2.65 an hour, the federal wage floor for all adult workers.

Richard R. Seideman, executive secretary of the minimum wage board, said the highest minimum wage in the nation currently is the statewide figure of $3.15 an hour in Alaska. The highest D.C. minimum is $3 an hour for laundry and dry-cleaning workers, which went into effect earlier this year.

Under D.C. law, the wage board sets different minimums for nine classes of workers. The current rates range downward from the $3 for laundry workers to a bottom - on paper - of $2.43 for some classes of manufacturing workers.

However, when D.C. minimums fall below the federal wage floor, currently $2.65 and scheduled to rise to $2.90 next January, the higher federal figure applies.

A committee of the D.C. City Council is considering legislation by Hilda H. Mason (Statehood-At Large) to raise the citywide minimum to $3.25 an hour starting next year, with annual future increases tied to an economic index.

"Wow!" Mason exclaimed when told of the proposed $3.50 for domestic workers. "Every crack in the door helps get the door open."

Paula Jewell, chairwoman of the three-member minimum wage board, indicated she was receptive to the proposal, but said she would not make up her mind until after the public hearing.

Jewell said one factor that weighs in favor of higher wages for domestic workers is their lack of such benefits as sick leave, retirement and vacation. Many workers also pay high transportation costs from their own pockets, she added.

The advisory panel was headed by the Rev. Sean O'Malley, a Catholic priest who works with the city's Hispanic community.

The panel's vote for the $3.50 minimum was 6 to 3, with the six public and labor representatives favoring it and three management representatives opposed.

Seideman said the majority filed only its factual recommendation. One management member, Jesse Zeeman, filed a minority report accusing the majority of reflecting "a naivete, an almost incredulously idealistic but impractical understanding of the workers of the economic system," with a likely effect of creating unemployment from overpricing.

In reaching its recommendation, the advisory panel cited figures indicating that an individual living alone in Washington would need earnings of at least $3.56 an hour to maintain a healthy existence.

Current wages for domestic workers were found to vary widely, from just above the minimum wage of $2.65 to $7.03 an hour for unionized office-building cleaners.

The $3.50 proposal would permit employers to continue to deduct from cash wages the cost of meals and lodging provided to workers. The new figures are 75 cents for breakfast, $1 for lunch and $1.25 for dinner, and $15 a week for a room.

The advisory panel also recommended a minimum wage of $2.90 for casual yard workers, notably youth employed cutting lawns, doing garden chores and shoveling snow in winter-time.