The survey, carried out on behalf of the Catholic Church's marriage preparation and counselling service, Accord, also found that 48% of couples planning to get married would have done so before now if it was not for the housing situation.
One third of those surveyed said they would have married within the last three years but did not.
The report found that 60% of couples planning to have children would have done so before now if it was not for the housing situation, with 36% saying they would have had a child in the past three years but did not.
The director of Accord, Tony Shanahan, said the findings were "significant and striking".
Mr Shanahan said they reveal the extent to which the lack of housing supply is impacting on the decision-making of couples who wish to get married and have children.
He added: "This has serious social implications now and into the future."
The results of the research were published to coincide with the blessing of rings of two engaged couples at the Carmelite Church on Whitefriar St in Dublin - which is home to the relics of Saint Valentine.
"I definitely feel that the young people and Irish people as a whole have been let down terribly."
One of the couples, Louise O’Reilly and David Lovett, have been together for 14 years and plan to get married next year.
They said housing was a factor in their decision not to get married sooner.
'We have been together a really long time, so I guess it was just a number of life things that maybe got in the way.
"But, overall, I absolutely agree with those statistics. It's incredibly hard.
"What's happening now in this current housing environment…and I definitely feel that the young people and Irish people as a whole have been let down terribly," Ms O’Reilly said.
'Other frills'
Bishop Denis Nulty has said he hears about delays all the time from colleagues.
"They tell me that very clearly that couples are putting off settling down because they don't have the foundation of the home."
Asked if it was a price of a wedding as opposed to the cost of a marriage that was putting people off, he said a move to simpler celebrations might be in order.
"I always say in church; the wedding is not a huge cost by any means to any couple. The bigger part is the other frills they'll do around it.
"So, I think we've got to get back to more simpler wedding receptions for people and more simpler celebrations," Bishop Nulty said.
The survey also found that lack of housing where couples live is causing a delay for 39% of those affected, and the cost of renting for 37% of couples.
Just over half, 54%, aged between 25-34 said they plan to get married and/or have children.
"The hope that young people hold for a married life together, and to start a family, needs to be underpinned by certainty in a functioning and affordable housing market," Mr Shanahan said.
The survey, which was conducted online and carried out last month by Amárach, involving 1,000 adults throughout Ireland.
Accord also reported that the number of couples who participated in their marriage preparation courses fell last year, down from 7,281 in 2023 to 5,194 last year.