The attorney general in the US state of Colorado has asked a county clerk to stop issuing marriage licences to same-sex couples.

Hillary Hall, a rogue county clerk in Boulder County, Colorado married 34 same-sex couples – including a state senator – despite the state maintaining a ban on same-sex marriage.

Now solicitor general Dan Domenico, has said the licences were prematurely issued and should not have been.

“It is clear that your office and ours have a difference of opinion regarding your authority to issue marriage licenses that do not comply with existing Colorado law,” Domenico wrote in a letter to Hall.

He also threatened to join up with the state to file a joint petition to find a resolution as to whether she has the authority to issue the marriage licences.

Hall opted to start performing same-sex marriages after the 10th Circuit Court of Appeals – whose jurisdiction includes Colorado – upheld a ruling striking down Utah’s same-sex marriage ban.

Despite the ruling, Colorado’s Amendment 43 – which defines marriage as only between a man and a woman – is still technically in effect, leaving Hall’s authority in question.