A judge has issued a permanent injunction against Alabama's law that bars same-sex marriage, saying state officials must follow the U.S. Supreme Court ruling last year on the matter.

In her decision, U.S. District Judge Callie Granade said she issued the permanent injunction because "as long as the Sanctity of Marriage Amendment and the Alabama Marriage Protection Act remain on the books, there continues to be a live controversy with respect to which the Court can give meaningful relief."

In March last year, the Alabama Supreme Court ordered probate judges to stop issuing same-sex marriage licences because of an existing state law, LifeSiteNews reports.

Chief Justice Roy Moore issued an administrative order last January telling state judges that the ban on same-sex marriage is still valid and that they should not issue same-sex marriage licences.

Last March, the Alabama Supreme Court issued a ruling to reject the U.S. Supreme Court decision that legalised same-sex marriage.

Granade's injunction covers probate judges and others "who would seek to enforce the marriage laws of Alabama that prohibit or fail to recognise same-sex marriage," AL.com reports.

But Liberty Counsel disagrees with Granade's ruling.

"This federal judge has no authority over the Alabama Supreme Court," said Matthew Staver, founder of Liberty Counsel. "This is by no means the final order because this lower federal court cannot direct the Alabama Supreme Court to act one way or another."

Staver accused the judge of "acting as if she is the top appellate court in the state."

"The only Court that has authority over the Alabama Supreme Court is the U.S. Supreme Court. The other parties are free to ask the U.S. Supreme Court to review the case but they have refused to do so. Judge Granade is not the U.S. Supreme Court," he said.

Associate Justice Tom Parker said the U.S. Supreme Court decision was "not based on law, but on the bare majority's philosophy of life."