The Prince George's County Council urged school officials yesterday to delay action on a proposed expansion of the county's magnet school plan, citing concerns that the desegregation program is not distributing money fairly among students and a sense that parents need more time to study it.

"We're hearing from all our constituents in the county that [school board members] are moving too fast," said council member Hilda Pemberton. "We need to have an understanding of how our money is spent and if it's spent wisely."

Pemberton and another member, Jo Ann T. Bell, said they would vote against funding the magnet program if their concerns were not answered. The council, which voted 8 to 0 to send a letter to the school board requesting detailed information about the cost of the plan, cannot veto line items in the school budget, but has authority over broad categories of funding and could deny the $12.9 million needed for next year's program.

The school board is to act on the magnet school expansion March 13. That vote was to have taken place this week but was postponed to give members more time to study the plan.

Board member Doris Eugene said she was "disappointed and surprised" by the council's action. "I don't see that you accomplish anything by delaying it . . . . We're on a roll. We've got the public with us," she said.

School spokesman Brian J. Porter said the board members were willing to meet with the council but "so far haven't heard any substantive reason why they shouldn't move forward," although he said the proposal may be modified.

The expanded plan would create 16 new magnet schools in 1986-87 and four more the following year, offering special programs to attract students from other neighborhoods to integrate those schools.

The plan, announced last month by Superintendent John A. Murphy, also would create 10 "compensatory educational" schools, five on a permanent basis and five temporarily. Those predominantly black schools would receive additional resources and programs because officials say they cannot be desegregated.

Pemberton cited figures indicating that black students were receiving less favorable treatment under the plan, including lower per-pupil expenditures. Porter, however, branded such figures "absurd."

Pemberton also said she was concerned that students in conventional programs were not benefiting. "Nobody has demonstrated that the average kids are being lifted up," she said. "Only the cream of the crop are being paid attention to, or those at the very bottom."

Eugene said the goal of the program was to bring schools within guidelines for racial balance. She said officials would focus later on equitable distribution of resources.

All children, she said, "are getting what the thrust of this program is, which is to desegregate."