Support for the introduction of same-sex marriage is rising steadily, with a majority supporting the move, the latest Irish Times/Ipsos MRBI poll has found.

Asked how they would vote in the planned referendum on the issue, 71 per cent said they would vote in favour, 17 per cent that they would vote No, 9 per cent had no opinion and 3 per cent refused to respond.

When undecided voters or those who refused to respond are excluded, the Yes figure rises to 81 per cent with 19 per cent on the No side.

That shows an increase since the last poll in October, when the figure, excluding undecided voters and those who refused to answer, was 76 per cent for Yes to 24 per cent for No. Back in November 2012, the margin was still closer, with 64 per cent Yes and 36 per cent No. The referendum is to be held next April or May.

In party terms, Labour voters are the most strongly in support of the move, with 80 per cent saying they will vote Yes, just 9 per cent No and 11 per cent undecided or refusing to respond. Support among Sinn Féin voters is almost as strong, but supporters of Independents and smaller parties, as well as Fine Gael voters, are a little less enthusiastic.

Fianna Fáil voters are the least supportive of the move, with 60 per cent saying they will vote Yes, 26 per cent No and 14 per cent undecided.

In class terms there is almost equal support for same-sex marriage across the spectrum, with middle class voters marginally more in favour than working class voters.

However, farmers are significantly less enthusiastic, with 46 per cent in favour, 33 per cent against and 21 per cent undecided.

There is also a marked difference between the sexes, with women more likely than men to say they will vote Yes.