Only hours before the law was to take effect, a Supreme Court justice on Tuesday blocked implementation of a portion of US President Barack Obama's health care law that would have forced some religion-affiliated organisations to provide health insurance for employees that includes birth-control coverage. Justice Sonia Sotomayor acted on a request from an organisation 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 10am on 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 Rienzi. "The Little Sisters are an order of Catholic nuns whose religious faith leads them to devote their lives to caring for the elderly poor. Not surprisingly, they have sincere and undisputed religious objections to complying with this mandate," Rienzi said. The Obama administration crafted a compromise that attempted to create a buffer for religiously affiliated hospitals, universities and social service groups that oppose birth control. The law requires insurers or the health plan's outside administrator to pay for birth control coverage and creates a way to reimburse them. But, for that to work, the nuns would have to sign a form authorising their insurance company to provide contraceptive coverage, which would still violate their beliefs, Rienzi said.