Research suggests that US Congress members lags behind the public on marriage equality.

According to a database compiled by Human Rights Campaign, only 34 per cent of Congress supports marriage equality, compared to polls which suggest more than 50 per cent of Americans back the rights of gay couples to marry.

The data shows that 181 Congress members support marriage equality but 234 have made public statements against it.

A total of 122 have made no comment. Seventy-two per cent of Democrats support marriage equality, with nine per cent opposed and 19 per cent unclear or unknown.

Only one Republican in Congress supports marriage equality: Rep. Ileana Ros-Lehtinen of Florida.

“As a majority of Americans have come to support the ability of loving and committed gay and lesbian couples to marry, they rightfully want to know whether their elected officials share that fair-minded view,” said HRC President Chad Griffin.

“Many members of Congress are commendably with the public, but Congress is always a lagging indicator. It’s time for more of our leaders to get on the right side of history.”