A cross-border survey commissioned by RTÉ and the BBC has found two-thirds of respondents were either fairly or very comfortable with a close member of their family marrying someone of the same sex.
The results are likely to encourage campaigners who want Northern Ireland's Assembly to legalise same-sex marriage.
Two days ago the Assembly voted on a proposal to legalise same-sex marriage.
The measure was blocked by the Democratic Unionist Party, which deployed a measure called a petition of concern to do so.
This was after Assembly members had voted in favour of change by a one-vote margin, 53 votes to 52.
The RTÉ and BBC survey is likely to encourage same-sex marriage campaigners.
It found that 64% of respondents in Northern Ireland were either fairly comfortable or very comfortable with a close member of of their family marrying someone of the same sex.
South of the border the figure was 67%.
A special programme on RTÉ One television at 10.35pm tonight - Ireland's Call - will reveal the findings on a wide range of questions put to over 2,000 people from each side of the border.
Presented by Miriam O'Callaghan, the issues examined will include the level of support for a united Ireland.
