Energy company Airtricity has said it is increasing its standing charge for both electricity and gas from the 1 April because the number of its customers in arrears has doubled.
Of its 600,000 customers, 65,000 are in default, though 10,000 are engaging with the company to set up a payment plan.
Airtricity said it has had to double the number of staff allocated to collecting debt in its credit division.
The electricity standing charge will rise by €1.70 per month including VAT, or €20.43 a year.
The standing charge for gas will be hiked by €1.14 per month including VAT, or €13.62 per year.
Customers who source both gas and electricity from Airtricity will see their joint bill rise by €34.05 a year.
Airtricity said it is applying these charges six months later than other suppliers and stressed there will be no standing charge increase for customers with pre-payment meters.
Airtricity Managing Director Stephen Wheeler said they very much regretted the increases but that they were necessary.
He said they were conscious of the economic difficulties customers were facing in managing household costs including energy bills.
He urged customers in genuine difficulty to set up a suitable payment plan, install a pre-payment meter or contact Airtricity's Customer Service team
He said they had no plans to introduce a low user standard charge.
In a statement, the Commission for Energy Regulation said that competition among electricity suppliers for customers has resulted in the Irish electricity market being de-regulated since April 2011.
''This means that all electricity suppliers set their own electricity prices without prior approval from the regulator. It is up to the supplier to justify such changes,'' it added.
The CER said it encourages customers to shop around among energy suppliers to get the best possible price and service deal.
It also said it is continuing to monitor the market and if it sees evidence of customer harm, it is prepared to intervene.
