The organisation ALONE says there are more than 250 older people currently on its housing waiting list - the highest number ever.
The charity is not a housing organisation, but says its volunteers are helping more and more elderly people facing housing problems.
In 2019, it dealt with 1,700 housing cases where it provided support to older people.
ALONE has warned that more older people could end up in homeless hubs if more action to tackle the crisis is not taken.
It said this year it has worked with more and more people in their 70s and 80s receiving notices to quit, who find themselves with nowhere to go.
The charity also said that some of the older people it works with will be spending Christmas and New Year in B&Bs and unsecure forms of accommodation.
The Summary of Social Housing Assessments for 2018 released in recent weeks has shown that the number of people aged 70 and over applying for social housing has increased by 9.9% in just one year.
The only other increases were for people aged 60-69 years (2.6%) and under 25 (0.7%).
ALONE CEO, Seán Moynihan said: "This Christmas we want to ensure that people are aware of the impact the housing crisis is having on older people. Receiving a notice to quit when you are younger is extremely difficult, but this challenge is compounded when we reach our 70s and 80s, and especially so during the winter months.
"The experiences of older people are often forgotten in the narrative of the housing crisis, but people of all ages deserve a home at Christmas time."
If anyone has concerns for themselves or an older person they know, they can contact ALONE on 0818 222 024 or email the charity through its website alone.ie.