Some 71% of people say they will vote in favour of same sex marriage in the forthcoming referendum.

An Ipsos MRBI poll in the Irish Times shows 17% plan to vote no, while 9% had no opinion and 3% refused to respond.

But when undecided voters - or those who refused to respond - are taken out, the yes figure rises to 81% with 19% on the no side.

That is an increase since the last poll in October, when the figure - excluding the undecided - was 76% yes and 24% no.

The country is expected to go to the polls on the issue in April or May of next year.

The poll finds that there is almost equal support for same sex marriage across the social spectrum in all classes - with middle class voters slightly more in favour than working class.

But farmers are said to be significantly less in favour - with 46% yes, 33% no and 21% undecided.

It also finds that women are more likely to vote yes than men.