Bord Gáis is to introduce measures to help customers struggling to pay their bills.
In its annual report, the company said customer debt had serious social implications.
Over 115,000 customers are in arrears of two months - three times more than the figure for last year.
The company says it is working with customers in difficulty.
One solution it is encouraging is the use of pre-paid meters, though it says public acceptance of the scheme is weak.
Bord Gáis wrote off €26.4 million in bad debts last year as a result of customer arrears.
It says turnover grew by 12% to €1.51bn last year, and profit before tax was stable at €120m.
Bord Gáis says that last year was difficult for its customers, but despite these difficulties the State-owned energy supplier warns that its prices may increase this year, as wholesale energy prices are a concern.
