A Metro committee endorsed a controversial multimillion-dollar plan yesterday to provide special lifts on half the transit system's buses by the mid-1990s to improve service for passengers in wheelchairs and other disabled riders.

Arlington County Board Chairman Mary Margaret Whipple, who heads the Metro committee, praised the move as a significant step that would result in a "good level of service" for disabled passengers.

But the plan was criticized as inadequate by a group representing handicapped riders and by D.C. City Council member Hilda Mason (Statehood-At Large), a Metro board member. The opponents called for quicker action, arguing that half the buses should be equipped with lifts before the mid-1990s.

In another move, the Metro committee recommended a series of measures to reduce friction between the Metrobus system and local governments that operate their own bus systems. The proposals include key changes in a long-debated formula governing subsidies paid by local governments for Metrobus service.

The committee also recommended streamlining Metro's long-criticized procedures for making changes in bus routes, and the panel sought to allay fears among some county and city officials by voting not to levy fees on local bus systems for use of bus stops and other facilities at Metro subway stations.

The plan for providing more buses with lifts and the proposals for improving ties between Metro and the local bus systems were both drawn up after months of debate by Metro and other officials. The two moves are expected to be approved by Metro's board of directors soon, possibly next week.

According to a recent consultant's study, the plan to provide half the buses with lifts would cost the financially pressed transit authority $5 million a year for new equipment, increased maintenance and other expenses. But some officials contended yesterday that this estimate may prove too high.

Whipple called for a further study of the cost estimates, citing possible flaws in the way the costs of repairing and maintaining the lifts were calculated. The group representing handicapped riders argued that half the buses could be equipped with lifts for $2 million to $3 million a year.

Metro now has 225 buses with lifts, 14 percent of its 1,572 vehicles. Under the new plan, half the buses the authority buys each year would have lifts. The handicapped group argued that all buses purchased by Metro should be equipped with lifts until the goal of providing lifts on half the buses is reached.

A national group called ADAPT, an acronym for American Disabled for Accessible Public Transit, has adopted a tougher stand than the local advisory committee, which represents handicapped and elderly Metro passengers. ADAPT has staged demonstrations here to demand lifts on all buses.

The proposals to ease conflicts between Metro and local bus systems stemmed from moves by several local governments in recent years to start their own bus services. Locally operated bus systems have been established in Montgomery and Fairfax counties and in Alexandria.

The plan to revise the formula under which counties and cities subsidize Metrobus service was designed to dampen the impact of any further expansion of locally run bus systems.

Under the proposal, officials said, governments that cut back on Metrobus service would save less money than previously, while governments that expand Metrobus service would not have to pay as much. As a result, other local governments would face less severe shifts in Metrobus subsidies.