The manufacturer has decided to issue a worldwide recall on the device
Samsung is suspending sales of its Galaxy Note 7 smartphones after some of the batteries exploded.
Some buyers reported their phones caught fire or exploded while they were charging, and Samsung said it had confirmed 35 such cases, caused by faulty batteries.
Since late last month, several users have posted photos and videos on social media showing the charred Note 7 with part of its 5.7-inch touchscreen burnt and melted, saying it suddenly caught fire.
Affected customers in Ireland can contact 01 6950367 to arrange a replacement over the coming weeks.
The president of the firm's mobile business, Koh Dong-jin, said an investigation by the company found a battery cell made by one of its two battery suppliers caused the phone to catch fire.
He refused to name the battery supplier.
He said: "We have received several reports of battery explosion on the Note 7 that was officially launched on 19 August, and it has been confirmed that it was a battery cell problem."
He added he was "deeply sorry" over the incident and customers who already bought Note 7 would be able to swap them for new smartphones, regardless of the purchase date.
The South Korean company said in a statement it would take about two weeks to prepare replacement devices.
The announcement comes just two weeks after Samsung launched its latest flagship smartphone.
The firm said it had sold more than one million Note 7 smartphones in 10 countries so far including South Korea and the US.
It has manufactured about 2.5 million Note 7 phones so far, some of them still in inventory.
The planned release of the Note 7 in several European countries has now been suspended over growing safety concerns.
Samsung has said China is not affected by the sales suspension, because it used a battery made by another supplier for the Note 7 sold there.