A senior Reagan administration official chose a storefront private school on Georgia Avenue NW last night to promote a controversial plan that would give parents of disadvantaged children federal aid to help pay private school tuition.

Under Secretary of Education Gary Bauer, the No. 2 official in the Education Department, spoke to a small and sympathetic crowd of about 50 parents at the private day-care center in what was billed as the first of a series of "town meetings."

While generally supportive of the administration's idea, the crowd of parents had one major complaint: the Reagan plan does not go far enough to meet their needs.

The plan would drastically alter the 20-year-old federal program for children who perform below their peers. It would give federal aid directly to parents, in the form of a voucher, or chit, redeemable at any participating private school or public school outside the child's home district.

The average amount of a voucher would be about $600, but would be more than $1,000-per-child in the District.

Bauer told the crowd that this plan was only a "first step," and if it is approved, the administration would propose expanding it to cover parents -- like many of those present last night -- whose children were not necessarily disadvantaged or underachievers.

Bauer's unusual appearance at the Academic Enrichment Center at 6119 Georgia Ave. NW represented a new strategy to convince inner-city and minority parents that the plan benefits the poor. Past plans to aid private school students have been criticized as helping only Catholics, wealthy suburban parents or families who want to take their children out of integrated public schools.

"Those in the chorus of opposition to vouchers have many things in common," Bauer said. "They are afraid of competition and they are afraid to let parents make basic choices."

The plan, unveiled two weeks ago, already has been criticized by the powerful education lobby, and has received little support on Capitol Hill. But it is still being touted as a major initiative for the department.

Bauer, the administration's point-man on the issue, said last night that "the voucher plan contains a simple message -- we care about you and your children."