A federal judge has instructed a county clerk in the US state of Illinois to issue marriage licences early to any same-sex couple who wish to wed immediately if one of them has a terminal illness.

Illinois Governor Pat Quinn signed the state’s equal marriage bill into law earlier this month, although weddings are not set to take place until June 1, 2014.

US District Judge Sharonh Johnson Coleman on Monday ordered the Cook County clerk’s office to marry any couples straight away if a doctor’s note can be provided to say that one of them is in a life-threatening illness.

US District Judge Thomas Durkin on Monday last month ordered the Cook County clerk to issue an expedited marriage license to Chicago couple Vernita Gray and Patricia Ewert.

Ms Gray is currently terminally ill with cancer, which has spread to her bones and brain. Doctors have told her she is not expected to live until June.

The two were later married.

Human rights advocates have speculated that this case may be the beginning of efforts to bring forward the effective date of the law signed by Governor Quinn.

He has said he would sign a bill to change the date if it came to his desk. “The sooner the better”, he said.