Private schools should not be discriminated against in their attempts to lease empty Montgomery County public school buildings, a task force appointed by County Executive Charles W. Gilchrist said yesterday.

The recommendation, made by a committee headed by former state school board president Richard Schifter, was immediately criticized by school board President Blair Ewing who had recommended to the committee that it come up with a proposal that would limit radically the number of private school tenants in surplus public school buildings.

Ewing was a leading opponent earlier this summer of the county's lease of the former Larchmont Elementary School building in Kensington to Grace Episcopal Day School. The Larchmont building is in the county's major school busing area. Opponents of the lease feared that parents seeking to avoid the integration plan would enroll their children at Grace Episcopal Day.

Schifter said yesterday that the five-member committee had considered proposals made by the board following the Larchmont controversy, but had concluded that the board's recommendations were neither fair nor good real estate management practices.

The school board's recommendations included barring private schools from leasing vacated public school buildings or allowing them to do so only if all efforts to find other tenants failed. The county, school board members argued, should not be in the business of underwriting the cost of running a private school at the expense of public schools.

The committee recommended yesterday that the county take a more active role in seeking out all possible tenants and consider allowing more than one organization to occupy a building.

The use of surplus public school buildings has become a major concern around the country as student enrollment continues to decline. In Montgomery County, 14 of the 49 schools closed since 1976 have been leased to private schools. County planners said yesterday private school officials have applied to lease three currently empty public school buildings.

Gilchrist said the report was excellent and in the best fiscal and policy interests of the county.