The governor of the US state of Maryland says he will sign a gay marriage bill into law.

The bill is currently progressing through the state Legislature and it is thought to have enough support to pass.

Democratic governor Martin O’Malley is in support of the measure, which has been gaining traction in the last week.

In a statement, Equality Maryland said: “This is the year Maryland will once and for all pass legislation to protect all of its individuals and families – from employment to marriage, it is time to treat all our citizens fairly.”

The group warned against legalising civil unions, which it said were not adequate.

Executive director Morgan Meneses-Sheets said: “Civil union doesn’t work. In other states with civil union, people have been barred from a dying partner’s bedside and denied the ability to say goodbye to the person they love. That just doesn’t happen when you’re married because everyone knows what marriage means.”

Massachusetts, Connecticut, Iowa, New Hampshire, Vermont and Washington DC already allow gay marriage. California did briefly before opponents got the law struck down.

If Maryland does allow gay marriage, the legislation may have to be defended in 2012 if opponents mount a challenge at the ballot box.

Last month, a poll of 1,030 Maryland voters found that a slim majority were in favour of the change.

The Washington Post poll found that 46 per cent support allowing same-sex marriage, compared to 44 per cent against and ten per cent who said they had no opinion.

In 2007, an identical poll question by the newspaper found 44 per cent in favor overall and 51 per cent opposed.