Many households and businesses are struggling to pay their energy bills, with more than one in 10 electricity and gas customers in arrears.
New figures released by the Commission for the Regulation of Utilities (CRU) show 11pc of all electricity users and 13pc of gas consumers were behind with their bills at the end of last year.
That equates to more than 376,000 families and small-businesses in arrears, of which nearly 170,000 were more than 90 days behind with their payments.
At the same time, there were also significant increases in the number of customers who had energy supplies cut off for non-payment of bills.
A total of 5,008 electricity customers were disconnected last year, an increase of 4pc over 2018.
However, the number of customers who had their gas supply cut off jumped by 40pc to 2,024.
The figures indicate two out of every 1,000 electricity customers and three of every 1,000 gas customers have been disconnected.
The regulator said the numbers could have been significantly higher, but for the number of consumers experiencing financial hardship who use pay-as-you-go meters.
The CRU has acknowledged that even more people may experience difficulty in paying their utility bills as a result of developments with the Covid-19 pandemic.
A temporary moratorium that was put in place on domestic electricity and gas disconnections from March 16 ended on June 29.
The regulator said it was continuing to monitor the market and will take action where appropriate to protect customers.
It noted that around 9,900 electricity customers and 2,000 gas customers were on payment plans.
Given the scale of the number of people and businesses in arrears, the CRU said there was scope for more of them to agree a payment plan with their supplier.
The CRU's annual Energy and Water Monitoring Report also shows 13.5pc of electricity customers and 17.7pc of gas customers switched energy provider last year.
Nearly a third of all switches were dual-fuel.
More than 323,500 electricity users switched supplier, which is down 2.5pc on 2018 levels.
Just under 124,700 gas customers moved to a new provider last year, a decrease of 9.1pc.
Although the number of customers switching supplier dropped last year, the CRU showed there were large increases in the number of electricity and gas customers who renegotiated their contract with their existing supplier.
Around 10pc of electricity customers and 12pc of gas customers sought a better energy plan from their provider.
The latest EU figures indicate Ireland has the fifth-highest switch rate among electricity users and the second highest rate among gas customers.
The CRU estimated that a customer who switched to the best available discount tariff each year for the past four years would over the period have saved up to €726 on electricity, €494 on gas and €1,343 on a dual-fuel bundle.