By Terry Baynes

(Reuters) - The University of Notre Dame and dozens of other Catholic institutions sued President Barack Obama's administration on Monday to block a government regulation that requires employers to provide health insurance coverage for contraceptives to employees.

The regulation, which is part of the president's healthcare reform law, has sparked a nasty fight between the administration and the Roman Catholic Church, which opposes artificial contraception.

Some 43 Catholic groups including Notre Dame, Catholic University of America and the Archdiocese of New York filed 12 different suits across the country.

The organizations accuse the federal government of forcing them to support contraception, sterilization and birth control in violation of their religious beliefs or face steep fines.

The original law exempted churches and other houses of worship from covering contraception on the basis of religious objections. But it did not carve out an exception for religious nonprofits, such as hospitals, charities and schools, sparking an outcry from church leaders.

As a compromise, Obama scaled back the controversial healthcare rule in February, announcing that insurance companies would cover the cost of the birth control for religious employers. But the complaints filed on Monday said the accommodation did not go far enough.

"In order to safeguard their religious freedoms, religious employers must plead with the government for a determination that they are sufficiently ‘religious,'" Notre Dame said in its lawsuit, filed in Indiana federal court.

Under the revised mandate, religious organizations can only qualify for the exemption if their purpose is to spread their religious beliefs. They must also primarily employ and serve people with the same religious values.

Such government scrutiny violates the separation between church and state, the suits claim. Notre Dame's complaint said it was unclear whether the school could qualify for the exemption, given its commitment to employ and serve people of all faiths.

Jane Belford, chancellor of the Archdiocese of Washington which joined one suit, said the groups aimed to challenge the government's redefinition of religion.

"While this mandate paid lip service to the rights of conscience and religious liberty, it created a definition that was so narrow, even the work of Mother Theresa would not have qualified as religious," Belford said.

The Department of Health and Human Services declined to comment on the litigation.

The U.S. Conference of Catholic Bishops, although it did not join any of the suits, praised the individual dioceses, charities and schools for defending religious liberty.

At least 11 other lawsuits have previously been filed against the contraceptive mandate, according to comments that the U.S. Conference of Catholic Bishops submitted to the Department of Health and Human Services on May 15. The submission included a warning about Monday's lawsuits: "Absent prompt congressional attention to this infringement on fundamental civil liberties, we believe the only remaining recourse ... is in the courts."

Jennifer Dalven, a lawyer at the American Civil Liberties Union, said the mandate was not new. Twenty-eight states have laws requiring insurers to cover birth control to the same extent as other medications.

"The lawsuits make it seem like taking a job is the same as joining a church. But organizations that participate in the public sphere are supposed to abide by public rules," Dalven said.

The suits were filed around the country, including in the District of Columbia, New York, Mississippi and Texas, according to Jones Day.

(Reporting By Terry Baynes; Editing by Greg McCune and Eric Walsh)