Officials in the third-largest county in Pennsylvania have said same-sex couples will be able to be issued marriage licences, despite a state-wide ban on equal marriage.

The state attorney general Kathleen Kane has said she will not defend the state’s ban on equal marriage, following a lawsuit being filed to challenge the ban.

The ACLU and the Philadelphia law firm Hangley Aronchick Segal Pudlin and Schiller, filed the complaint earlier this week in the US District Court, in an effort to have the state’s Defense of Marriage Act deemed unconstitutional.

D Bruce Hanes, the register of wills in Montgomery County in southeast Pennsylvania has said he wants to come down “on the right side of history and the law”, and agreed to issue a licence on Tuesday to two women who contacted him last week.

The couple later changed their minds, after a discussion with the ACLU of Pennsylvania, because of the pending lawsuit.

The attorney acting on behalf of the couple said the two women, both doctors in their 40s, had decided that “today is not the day”, because of fears their marriage may be overturned.

The attorney went on to say that the couple do still intend to marry, and intend to do so in the state.