A liberal open enrollment law that lets students switch schools for anything from history class to extracurricular hockey worries some educators and parents who fear it could severely unbalance Minnesota schools.

Residents of small towns are worried that under a new state law considered the broadest in the nation by educators, too many students will flee little districts unable to offer the variety of courses available in bigger districts."They're deathly afraid they're going to lose their school. It makes them sick at heart," said Richard Pearson, the state Department of Education's acting manager of district support services. "That's unfortunately a real possibility."

Under the plan passed by the Legislature in May, the state's large districts must give students the right to transfer without giving a reason, beginning in the 1989-90 academic year. The law permitted some schools to adopt the policy this academic year. It will apply to smaller districts in 1990-91.

Schools may refuse students only if the transfer would interfere with desegregation ratios in Minneapolis, St. Paul and Duluth, or if the school is too crowded.

While the law was intended to enhance academic, not athletic, opportunities, the Minnesota State High School League, which regulates sports, also is concerned about the open enrollment plan.

"My sense is a lot of people are worried," said Dave Stead, executive director of the league, which has 472 member schools.

Gary Addington, supervisor of athletics for Rochester public schools, said he hopes transfers solely for athletic reasons don't become widespread. "It could create great inequities between schools as far as competitiveness," he said.

The Education Commission of the States, headed by Gov. Rudy Perpich, is planning a national conference on open enrollment and other education options for Feb. 23-24 in Minneapolis, said Robert Wedl, deputy commissioner of the state Department of Education.

Only two districts - Edina, an affluent Minneapolis suburb, and rural Sartell in central Minnesota - met a Sept. 30 deadline to notify the state they will not admit students from other districts in 1989-90, Pearson said.

Sartell's decision was based on lack of classroom space, Pearson said. Edina, with its highly regarded school systems, said it wouldn't as a general rule accept transfer students but would review applications individually, Pearson said.

Members of a commission appointed by the governor to study education issues said Edina's decision set a precedent for other districts to reject open enrollment and could be viewed as a move to keep minority students out.

Edina officials deny that, saying parents expressed concern during school board meetings about students abusing the academic intent of the law.

"The principal abuses are with regard to athletics, specifically that of students selecting another school district for the purpose of participating in varsity sports within that school district, rather than for reasons of quality education," Dennis Maetzold, an Edina school board member, said Monday.

School officials say they hope districts such as Edina that decline to accept students across the board will be rare.