Organized labor and business spokesmen voiced totally opposite views yesterday on a proposal to raise D.C. minimum wages for parking lot attendants, car wash employes and a grab-bag of other workers to $3.90 an hour -- the highest government-enforced pay of any employe group in the nation outside Alaska.

For most affected employes, the adoption of the higher pay scale as proposed by the D.C. Wage-Hour Board would mean an increase of 55 cents from the federal minimum wage of $3.35 that went into effect earlier this month. The board has power to set wages inside the District for various occupational groups above the federal minimum.

Joslyn (Josh) Williams, representing the AFL-CIO Greater Washington Central Labor Council, led off testimony at a board hearing by contending that $3.90 would still be far too low to maintain a decent living standard in high-cost Washington. He said a range from $5 to $5.50 should be adopted. His view was supported by Thomas McNutt, a union official who represents retail store clerks and others.

In contrast, leaders of the parking garage industry told the board that increases in past years above the federal minimum wage have led to layoffs of parking attendants and increased automation.

Irwin Edlavich, president of Atlantic Garage Inc., a major operator, said his firm hired one attendant for every 44 spaces in 1975, a ratio that has since dropped to one attendant for 75 spaces. "The primary reason . . . is the increase in payroll [costs]," he said.

A. George Cook, a director of the Washington Parking Association and general manager of colonial Parking, Inc., said the limit of the industry's ability to cover higher wages by increasing customer prices is being reached.

Spokesmen for the car-wash industry said they would have to shut down or automate their businesses if the higher wage is adopted.

Paula L. Jewell, board chairman, said she expects a decision to be made late next month and that it should become effective around May 1.