The rise marks one of the largest changes in opinion on any policy issue in the United State over the 10-year period.
According to the results of a CNN/ORC International survey, 57 per cent said a member of their family or someone close to them was gay or lesbian - an increase of 12 points since 2007.
CNN Polling Director Keating Holland said the number of Americans who support same-sex marriage has risen by almost the same amount in the same time frame - from 40 per cent in 2007 to 53 per cent today - suggesting that "rise in support for gay marriage is due in part to the rising number of Americans who have become aware that someone close to them is gay".
Holland said some people had recently taken to calling the change in opinion the "Rob Portman effect," after the Republican senator from Ohio who learned that his son is gay and changed his hard line position on gay marriage as a result. Portman announced the news in an interview in an interview with CNN.
A poll carried out in Ohio also indicated that the public had switched sides on the same-sex marriage debate, nine years after banning it.
The results of the poll, released yesterday, showed that 54 per cent of Ohioans now support a new amendment which would repeal the ban and allow "two consenting adults to marry, regardless of their gender," The Columbus Dispatch reported.
Head of the firm that conducted the poll, Martin D Saperstein, attributed the rise in support to the number of young people who support gay marriage reaching voting age.
"Part of that comes as the media make gay people look more common," he told The Columbus Dispatch.
New Zealand's Marriage Amendment Bill is expected to return to Parliament tomorrow for the committee stages after easily passing its second reading by 77 votes to 44. It could become law next month.