More than 1.8 million people are struggling to survive on 100 euro or less a month after bills are paid, a study has shown.
Four out of 10 adults have borrowed to pay a household bill in the last year, with the most desperate 10% using a moneylender, it revealed.
The survey, by the Irish League of Credit Unions (ILCU), also found half of all bank account holders do not know what bank charges they pay on accounts.
Kieron Brennan, ILCU chief executive, warned it has never been more important for people to get in the practice of managing their money tightly.
"The issue of personal debt is something we are hearing more and more about and the issue is a growing concern, particularly for those who are relying on their credit card to make ends meet every month," he said.
"Even more concerning is that of those who are borrowing each month to meet payments on their household bills, 10% are turning to moneylenders.
"The ILCU recently called on the Government to put a legal cap on the interest rates charged by moneylenders in Ireland. No such cap currently exists but in practice, the ceiling is just below 190% APR.
"With the level of personal indebtedness and financial exclusion in Ireland, there is a real danger of compounding the problem by allowing legal moneylenders to charge excessive rates."
The "What's Left" Tracker survey quizzed 1,000 adults in June.
It calculated 1.82 million adults across Ireland have less than 25 euro (£20) left each week to spend after bills - a jump of 200,000 people in the last year.