A poll of Catholic voters in the US state of New Jersey has shown that just under half are in favour of gay marriage.

The state’s Senate was due to vote on a gay marriage bill today but this has stalled after Democrats said they wanted to strengthen support.

There are fears they do not have the 21 votes needed to pass it.

The poll from Rutgers-Eagleton surveyed 903 people in early November, asking them about their religious beliefs and views on marriage equality.

Among Catholics, 48 per cent supported gay marriage, while 40 per cent opposed it and 12 per cent were undecided.

Protestants held the opposite view, with only 34 per cent supporting and 55 per cent opposing gay marriage, and 11 per cent undecided.

Jewish respondents supported gay marriage 56 per cent to 40 per cent and four per cent undecided, while those with no preference are the most supportive, at 85 per cent to only ten per cent opposed with five per cent undecided.

David Redlawsk, director of the Rutgers-Eagleton Poll and professor of political science at Rutgers University, said: “As with several social issues, many Catholics support a more liberal public policy than does the church itself.

“Given that Catholics comprise the single largest religious group in the state, this makes a difference in overall support for gay marriage in New Jersey, especially since a majority of Protestants – many of whom are evangelicals – oppose the bill.”

The bill will now be debated in the Assembly Judiciary Committee, where support for gay marriage is said to be stronger. A date has not yet been scheduled.

Supporters hope it can return to the Senate for a vote before this legislative session ends. Governor-elect Chris Christie takes over in late January and has made his opposition to gay marriage clear.