A family and a group of Christian schools have filed a discrimination suit against the U.S. state of Montana over a state scholarship programme regulation that excludes religious schools.

The lawsuit was filed against Mike Kadas, director of the Montana Department of Revenue, for implementing a programme that prevents students from any religious school from using the funds under the state's Scholarship Tax Credit Programme.

Kathy and Jerry Armstrong, parents of a student studying at a religious school in Montana, and the Association of Christian Schools International filed the lawsuit. They are being represented by the Pacific Legal Foundation (PLF).

The PLF says the ban violates the First and Fourteenth Amendments of the U.S. Constitution and the Montana Administrative Procedure Act.

According to the lawsuit, the Scholarship Tax Credit Programme allows individuals and businesses to claim a tax credit for donations to authorised Student Scholarship Organisations, which use the money to create scholarships for students to use at accredited private schools in Montana.

The Association of Christian Schools has about 3,000 school members in the U.S. including 11 in Montana.

"Not only is the Department thumbing its nose at fundamental constitutional values, it is also usurping the authority of the Montana Legislature. Unelected officials are taking on the role of lawmakers by rewriting the school choice programme. They're inserting arbitrary restrictions into a programme that was intended for all accredited private schools and their students, regardless of any religious affiliation," said PLF attorney Wencong Fa.

Fa explained that "the state constitution's prohibition on government subsidies for religion has absolutely no application to the scholarship tax credit programme. As the U.S. Supreme Court has put it, a tax credit system is a privately operated programme, 'implemented by private action' and involves 'no state intervention.'"

The law allows any "qualified education provider," which means any accredited private school, to join, WND reported.

According to the Armstrongs, whose son studies at Valley Christian School, "this kind of anti-religious bias is offensive to us as parents, as people of faith, and as Americans."

"Unelected bureaucrats cannot be allowed to undermine a promising school choice programme, especially with restrictions that punish people based on their religion," said Fa. "Either the agency withdraws these unseemly and unconstitutional proposals, or it will need to answer for them in court."

The association said excluding "certain schools and students merely because they have a faith commitment, is counterproductive and wrong."