The CER says a "significant number" are vacant properties
New figures show there were 806 disconnections of domestic electricity customers for non-payment in March.
The Commission for Energy Regulation (CER) says this compares to 592 for the same period last year.
While the total number of disconnections in gas for March was 363, compared with 300 disconnections in March last year.
Disconnections data is received on a monthly basis by the CER.
However, the CER adds that this data covers a period where suppliers are not permitted to disconnect registered vulnerable customers.
A vulnerable customer is defined as a household customer who is critically dependent on electricity powered equipment - or particularly vulnerable to disconnection during winter months for reasons to advanced age or physical, sensory, intellectual or mental health.
The CER also says "anecdotal evidence" from suppliers suggests a significant number of disconnected properties are in fact vacant.
"The number of disconnections of customers in difficulty may be much lower than that suggested by the data", it adds.