Moves to overturn the equal marriage ban in the US state of Ohio are building momentum, with a three-city announcement of the Why Marriage Matters campaign.

The group is backed by the Equality Ohio Education Fund, Freedom to Marry, the Human Rights Campaign Foundation and the American Civil Liberties Union (ACLU) Foundation.

The three cities in which the campaign kicked off were Clevelant, Columbus, and Cincinnati. State Representative Nickie J Antonio, a Democrat, and Ohio’s only openly-gay legislator, said she supported overturning the ban.

Elyzabeth Holford, executive director of Equality Ohio said the group was supportive of a constitutional issue to overturn the ban on same-sex marriage, but did not say when.

“There are couples in Ohio living in legal limbo. It’s time to change that. Why Marriage Matters Ohio is part of our roadmap to fairness and dignity for all Ohioans,” she said in a statement.

Equal marriage advocacy group Freedom to Marry Ohio hopes to put a constitutional amendment on the ballot for Ohio later this year or next, which would remove the 2004 amendment which banned equal marriage. It has been collecting signatures on a petition, however other LGBT organisations have not yet signed up.

“We are committed to bringing full equality to every Ohioan in all aspects of life. That means employment equality, housing equality, and marriage equality,” said Christine Link of the ACLU.

A poll released last week by Public religion Research Institute showed public support for equal marriage as evenly split at 47%

In 2004, the amendment banning equal marriage passed with 62% of voters supporting.

Back in July US District Judge Timothy Black ruled in favour of a couple who filed the lawsuit challenging the constitutionality of the Ohio state-wide ban on equal marriage.James Obergefell and John Arthur filed the lawsuit as Mr Arthur is terminally ill, and with a view to having his death certificate to show that the couple are married.