In the debate over control of development in fast-growing Montgomery County, the County Council unanimously opposed yesterday asking the General Assembly to increase the county executive's planning power.

Council members spent more than four hours debating the seven bills that have been submitted by County Executive Charles W. Gilchrist to the county's legislative delegation. Members of the local Senate delegation are scheduled to hold a public hearing on the proposals Tuesday, but the council unanimously passed a motion yesterday urging the delegation to withhold action until council members can meet with Gilchrist and work out a compromise.

"What we are talking about is a power play," said council member Rose Crenca.

Gilchrist's special assistant Edmond Rovner said that the county executive would be happy to meet with the council. The meeting can be held immediately, he said, without interfering with the delegation's schedule.

The council members said they oppose any changes by the state legislature on the grounds that it would set a dangerous precedent to have the state address local county planning problems.

Yet they also voiced approval of some of the changes that Gilchrist wants to make in the county planning system. For instance, they endorsed giving the county executive veto power over subdivision regulations and zoning law amendments. The council could override the veto with a five-vote majority, under the proposal. The executive has no veto with the current system.

At the same time, the council members said they opposed Gilchrist's proposal that the county executive, rather the council, appoint county planning board members.

This proposal is regarded as the most controversial of the seven. A statement prepared for the council by Planning Board Chairman Norman Christeller, and endorsed during the debate by many of the council members, said, "It is going too far . . . to provide that the executive shall appoint the council's principal advisers on the planning process, the body to which the council has delegated the responsibility for subdivision approval and site plan review."

Gilchrist takes the position that the county executive appoints almost all of the 60 county boards and the council then confirms the members, and the planning board should be the same.

The council also questioned Gilchrist proposals calling for:

*Executive administration of the Adequate Public Facilities Ordinance, which governs the way in which new developments are approved. The council agreed that the executive's role in this process should be strengthened, but council members want more discussion on how that should be done.

*Limiting tenure on the planning board to two four-year terms and eliminating provisions that allow for full-time board chairmen.

*Executive veto over master plans for future development.

The Gilchrist proposals were developed after a blue-ribbon committee concluded last month that the root cause of county growth problems lies with the "fragmentation of responsibilities" for development between the council and the executive.