A judge in the US state of Missouri is hearing arguments in a case over whether to stop gay married couples from filing joint tax returns.

Cole County Circuit Judge Jon Beetem, on Thursday heard arguments following a request for a temporary restraining order on an order given by the state’s Governor allowing same-sex couples to file joint tax returns.

Governor Jay Nixon filed the order, which made Missouri the first state which does not recognise same-sex marriages, to make such a move.

The lawsuit challenges the executive order, asserting that it breaks Missouri’s constitutional provision which recognises marriage specifically as between one man and one woman.

Missouri Attorney General Chris Koster, confirmed that the order was in line with the state law.

Nixon said his opinions on equal marriage had changed. He said: “I just don’t think we should treat folks differently in this zone anymore.”

Missouri was the first state to pass a constitutional amendment banning equal marriage, in response to a Massachusetts court decision to legalise equal marriage there.