Same-sex marriage has been legalised in the US state of Wyoming, after officials filed a notice saying they would not continue to defend a law banning it.

Clerks around the state will be able to immediately issue marriage licences to gay couples.

Lawyers for the state of Tuesday filed a notice that the state would not defend the law which defined marriage as specifically between one man and one woman.

On top of this, the state will recognise marriages performed between same-sex couples out-of-state.

A judge last week struck down a ban on same-sex marriage in the state of Wyoming.

Celebrations are planned for the state later in the day.