The Society of the St Vincent De Paul says it is afraid struggling families may turn to money lenders to cope with Christmas debt.
The warning from the charity follows media reports that a petrol bomb attack on a Waterford home was carried out after the family used the services of a local money lender.
A 23-year-old man appeared in court earlier charged with reckless endangerment and criminal damage as a result of the attack which left two children with severe burns.
Brendan Hennessy, the Social Justice Officer for the Vincent de Pail, said: "The fear of St Vincent de Paul members around Christmas is not so much Christmas time itself, it's post-Christmas when people find themselves having to go to money lenders and so forth to meet basic needs.
"Our encouragement to people is to try to use whatever means they have at the present, if that's possible at all.
"But also coming up to Christmas to recognsze that this has become a very expensive country to live in and we all must measure our expectations with that in mind."