The Governor of the US state of Utah has defended his decision to continue to fight to enforce a same-sex marriage ban, despite estimated costs of at least $300,000 to hire outside counsel.

Between 20 December and 6 January, some 1,300 couples married in the state as a US District Judge ruled that a ban on same-sex marriage violated the state’s constitution.

The US Supreme Court since put a stay on equal marriage in the US state, forbidding same-sex couples from being issued with marriage licences in the state during an appeal against a ruling to allow them.

The Utah Attorney General Sean Reyes advised Governor Gary Herbert that marriages between gay couples who married in that short period should not be recognised by the state for benefits purposes.

Herbert has now accused US District Judge Robert Shelby of being an “activist”, and said his strike-down of the same-sex marriage ban was one step away from a “dictatorship”.

“I think that’s very, very dangerous, in fact, when we have elected officials picking and choosing which laws they’re going to enforce,”

He said the state needed to “put its best foot forward in defending its Constitution”, and defended the fact that it will cost taxpayers in the state at least $300,000 (£180,000) to pay to hire outside counsel when it goes to the 10th Circuit Court of Appeals.

“The debate shouldn’t be same-sex marriage. It should be states’ rights,” Herbert continued, but said it had not been: “Because you have an activist on the bench.”

He went on to further criticise Judge Shelby’s decision to deem the ban unconstitutional, saying: “I have empathy for their plight,” Herbert said. “I have empathy for … their confusion that’s been created by the Judge Shelby ruling.”

On 8 January, the same day that Governor Gary Herbert issued the directive not to recognise the marriages, the civil liberties group the ACLU began looking for plaintiffs, and on Tuesday it filed a lawsuit against the state.