Only hours before the law was to take effect, a Supreme Court justice on Tuesday blocked implementation of part of President Obama's health care law that would have forced some religion-affiliated organizations to provide health insurance for employees that includes birth control coverage.

Justice Sonia Sotomayor's decision came after a different effort by Catholic-affiliated groups from around the U.S. Those groups had rushed to the federal courts to stop Wednesday's start of portions of the Affordable Care Act, also known as Obamacare.

Sotomayor acted on a request from an organization of Catholic nuns in Denver, the Little Sisters of the Poor Home for the Aged. Its request for an emergency stay had been denied earlier in the day by a federal appeals court.

The government is "temporarily enjoined from enforcing against applicants the contraceptive coverage requirements imposed by the Patient Protection and Affordable Care Act," Sotomayor said in the order. She gave government officials until 10 a.m. EST (1500 GMT) Friday to respond to her order.

The law requires employers to provide insurance that covers a range of preventive care, free of charge, including contraception. The Catholic Church prohibits the use of contraceptives. That was not acceptable, said the nuns' lawyer, Mark L. Rienzi.