Supporters of same-sex marriage hold signs outside the Jefferson County Courthouse in Birmingham, Alabama February 9, 2015. [Photo/Agencies]

Moore is no stranger to controversy. In 2003, he was removed from office after defying a federal order to take down a Ten Commandments monument he had erected in the state's judicial building. He was returned to his post by voters in 2012.

US District Court Judge Callie Granade, an appointee of President George W. Bush, ruled in January that Alabama's same-sex marriage prohibition was unconstitutional, putting her decision on hold until Monday.

Two of the US Supreme Court's conservative justices, Clarence Thomas and Antonin Scalia, dissented from the decision not to further delay gay marriage in Alabama.

In a dissenting opinion, Thomas wrote that the high court's actions in allowing marriages to go ahead "may well be seen as a signal of the court's intended resolution of that question."

In April, the Supreme Court is set to hear oral arguments in cases concerning marriage restrictions in four states. A ruling, due by the end of June, will determine whether the remaining 13 state bans can remain intact.