A federal appeals court ruled that gay marriages can continue in Utah, denying a request from the state to halt same-sex weddings until the appeals process plays out.

The court rejected the state's request for an emergency stay on a federal judge's ruling that found Utah's same-sex marriage ban violates gay and lesbian couples' rights.

The judge who made that ruling, Judge Richard Shelby, refused the state's first request to put a halt to the marriages Monday.

Utah's last chance to temporarily stop the marriages would be the U.S. Supreme Court.

The appeals court ruling means county clerks can continue to issue marriage licences to gays and lesbians. Nearly 700 gay couples have obtained marriage licences since Friday, with most coming in the state's most populous county.

Utah is the 18th state where gay couples can wed, and the sight of same-sex marriages occurring just a few kilometres from the headquarters of the Mormon Church has provoked anger among the state's top leaders.

"Until the final word has been spoken by this court or the Supreme Court on the constitutionality of Utah's marriage laws, Utah should not be required to enforce Judge Shelby's view of a new and fundamentally different definition of marriage," the state said in a motion to the appeals court.

Shelby's decision to strike down a law passed by voters in 2004 drew attention given Utah's long-standing opposition to gay marriage and its position as headquarters for the Mormon Church.

Nearly two-thirds of Utah's 2.8 million residents are members of the Church of Jesus Christ of Latter-day Saints, and Mormons dominate the state's legal and political circles.

Gay Marriage-Utah

Hundreds of same-sex couples descended on Utah county clerk offices Monday after the state struck down a ban on gay marriage last week. (Francisco Kjolseth/Associated Press)

In court Monday, Utah lawyer Philip Lott repeated the words "chaotic situation" to describe what has happened in Utah since clerks started allowing gay weddings. He urged the judge to "take a more orderly approach than the current frenzy."

"Utah should be allowed to follow its democratically chosen definition of marriage," he said of the 2004 gay marriage ban.

That confusion stretched to county clerks in Utah, some of whom were refusing to issue marriage licences to gay couples, even though they could face legal consequences.

The Utah attorney general's office warned counties they could be held in contempt of federal court if they refuse to issue the licences.