Nearly 100 soccer and softball enthusiasts mustered in Rockville last night to complain about a plan to charge fees for using athletic fields at Montgomery County parks.

"Once a user-fee is levied, then they'll start talking about when to raise it," said Terry Shea, 38, a Gaithersburg resident who rushed from two soccer team practices to the public hearing before the Montgomery County Council.

"Soccer is a wonderful sport," said Shea, whose husband and two children, aged 12 and 9, have played in the popular Montgomery Soccer Inc. (MSI) league for several years. Shea said user-fees could force families like hers to abandon the sport, "and then where would kids look . . . for their soccer?"

On and off the playing fields of Montgomery, the debate over user-fees is raging this season, with a well-organized group of sportsmen and women fighting a relatively small, but powerful, band of local officials.

Led by council member William E. Hanna Jr., several officials are calling for a revamping of Montgomery's checkerboard fee structure, including new fees to offset the cost of maintaining recreation areas in the county, which now has 26,580 acres of parkland.

People like Shea, whose family members pay $18 to $21 each to play in the 7,700-player MSI league, and softball teams, each of which pays a $735 fee to the county, say charging them for fields they now use for free would amount to an unfair new tax.

"We admit we wear out the grass, but a user-fee would outweigh the benefit of our program," said Gordon Martin, an MSI spokesman who coaches and has two children in the league.

Martin said the group, which spends about $6,000 a year to help maintain the 50 schoolyard fields it uses, also is willing to help with the cost of maintaining the 15 park fields it uses each spring and fall.

Hanna called for a fee structure that would defray maintenance costs without barring the handicapped, poor, elderly, or other groups from public parks. He asked: "Should taxpayers pay the cost. . . of special-interest soccer? Someone has to pay."

It remains unclear what the fees would be, although in the case of soccer, a county fiscal affairs committee has recommended charging each team $28 to reserve a field for an eight-week season.

Fee opponents found one ally in council Vice President Michael L. Gudis, who said, "Recreation should be added to the list" of services, such as health and public safety, that "county citizens expect [to be] free.

"I have a real hard time with fees for recreation," said Gudis, who called free parks "part of what we pay taxes for."

Council members are expected to take several weeks before deciding what to do.