MADISON, Wis. (AP) — A group representing private schools in Wisconsin’s choice program sued the state education department Wednesday, saying it illegally forbids choice schools from counting online classes toward instructional time.

School Choice Wisconsin Action, through its attorneys with the Wisconsin Institute for Law and Liberty, filed the lawsuit in Waukesha County Circuit Court.

The lawsuit alleges that the Wisconsin Department of Public Instruction is illegally treating choice schools and public schools differently. State law allows public schools to count online learning toward the minimum number of instructional hours required each year.

In a Feb. 28 email to attorneys for choice schools, the department’s attorney said that state law would have to be changed to give the department the authority to count online classes at choice schools. A bill is circulating in the Legislature that would do just that.

A department spokesman had no immediate reaction to the lawsuit.

Both public and choice schools must provide 1,050 hours of “direct pupil instruction” in any given year for students in grades 1 through 6. The requirement is 1,137 hours for grades 7 through 12. That becomes a challenge for districts in years like this one when many schools closed due to snow and cold weather.

Schools looking to get creative in making up the lost hours turned toward offering instruction over the internet. In January, various private schools in the choice program asked the education department if they could offer online classes to satisfy the hourly instructional requirement.

The department responded in emails sent in February to School Choice Wisconsin’s attorneys. Department attorney Ben Jones said its interpretation of the law was that choice schools could not credit choice schools for virtual learning. The lawsuit contends that the department does not have the legal authority to make such a determination.

The lawsuit also argues that if the department wanted to make that determination, it would have to go through the formal rule-making process. By not doing that, the department is violating the constitution’s equal protection clause by treating private schools in the choice program differently than public schools, the lawsuit contends.

The choice schools want the court to allow them to offer online classes to meet the instructional time requirements and to prevent the education department from penalizing them for doing that.