Support for the introduction of same-sex marriage has declined since the beginning of the year but the Yes side still retains a strong lead, the latest Irish Times/Ipsos MRBI poll has found.
The poll also shows the Government is facing a comprehensive defeat on the proposal to lower the age of eligibility for presidential candidates from 35 to 21.
In the referendum on same-sex marriage, when undecided voters are excluded, support for a Yes vote stands at 74 per cent, down six points since the last poll in December, while support for the No side is up six points to 26 per cent.
It is the first time support for the Yes side has declined in an Irish Times poll since the question was first asked in 2012.
The latest survey was undertaken on Monday and Tuesday of this week among a representative sample of 1,200 voters aged 18 and over, in face-to-face interviews at 100 sampling points in all constituencies. The margin of error is plus or minus 2.8 per cent.
The findings show a difference in voting intentions across the age groups. Among the 18- to 24-year-olds, 84 per cent intend to vote Yes and 10 per cent No.
By contrast, in the over-65 age group, 43 per cent intend to vote No and 37 per cent Yes.
There is a significant gender difference, with women more inclined to vote Yes than men.
In party terms Fianna Fáil supporters are the least enthusiastic for a Yes, with Labour voters the most supportive of a Yes.
In the other referendum on May 22nd, the proposal to reduce the age for presidential candidates is likely to be defeated heavily.
Asked how they intended to vote on the proposed amendment, 62 per cent of people said No, 29 per cent said Yes and 9 per cent were undecided or said they would not vote.
The proposal, which emerged from the Constitutional Convention, is opposed by all age groups apart from the 18- to 24-years-old cohort.
Even a significant majority of the 24-35 age group intends to vote No.
In party terms, Fine Gael and Labour supporters are the strongest opponents of the move being proposed by the Government.
Some 71 per cent of Labour voters and 68 per cent of Fine Gael voters intend to vote No.