A new study on loneliness by the Irish Longitudinal Study on Ageing (TILDA) has found that one in ten of those over the age of 75 have reported feeling lonely "a lot of the time".
One of the report's authors, Dr Mark Ward, said one of the effects of an ageing population is that Ireland has increasing numbers of older adults living alone.
Speaking on RTÉ's Morning Ireland, he said it was a group that was particularly vulnerable and that the issue will only increase unless it is addressed.
He said the study found that there were similar levels of loneliness reported by urban and rural participants, but that small towns had higher rates of loneliness than urban centres.
Dr Ward said: "Other research that we've done has shown that the social context that people have is different between urban and rural areas.
"In rural areas it's more associated with traditional forms of social contact, like the church, whereas in urban centres people seem to replace that with other forms of organisations."
Pensioner Don Smith said he became lonely following the death of his wife 11 years ago.
Speaking on the same programme, he said he contacted ALONE, who sent him a 'befriender', which is a person who comes and chats to him once a week.
"It made quite a difference to my whole attitude to life. I worked in media and was always surrounded by people. I missed that a lot, especially in the beginning," Mr Smith said.
Dr Ward said Mr Smith's story was a familiar one and that retirement was a huge time of change in people's lives.
He said one of the key things to making the transition more successful was getting into "good habits" before retirement, such as taking up a hobby.
Mr Smith echoed this advice, saying: "Find something you're passionate about and develop it, because when you're retired you'll have lots of time to indulge in whatever you like.
"Even if it's just playing cards a few times a week. Find an interest that will occupy your time in a pleasant way."
Dr Ward said TILDA's aim with this survey is to raise awareness about the issue of loneliness among the elderly, and to make them aware that there are services out there - such as ALONE - that can help them.