The abduction of Co Fermanagh businessman Kevin Lunney has been described by Leo Varadkar as “reminiscent” of paramilitary attacks.
Mr Lunney, 50, a director of Quinn Industrial Holdings (QIH), was snatched near his Co Fermanagh home and brutally assaulted in September.
The father of six spoke out about the attack in a television interview last week, describing how he had been slashed with a knife, doused with bleach and branded by his captors before being dumped on a remote road in Co Cavan.
Criminals targeting QIH executives are believed to have been behind the attack.
A cross-border police investigation is under way but the perpetrators remain at large.
Mr Varadkar met the directors of Quinn Industrial Holdings on Sunday.
Speaking in an interview with BBC Northern Ireland’s Spotlight programme on Tuesday, the Taoiseach said he was horrified by the attack.
“I had obviously heard some media reports but I think it’s only when somebody recounts their own story that you can really get a full insight and understanding of what they went through and this was a planned, cold, calculated attack,” he said.
“He was essentially tortured and for me it brought back memories of the kind of attacks that paramilitaries used to carry out and on some occasions still do.”
The attack, during which his assailants demanded Mr Lunney’s resignation, was the most serious in a five-year campaign of intimidation targeting the companies and directors that now control the business portfolio which was built up by fallen tycoon Sean Quinn, once Ireland’s richest man.
A sinister element in the community in the Fermanagh/Cavan border area, where the QIH companies are based, continues to vent anger at the demise of Mr Quinn’s empire.
The Quinn family have consistently condemned and distanced themselves from those attacking the new owners.
A series of police searches connected with the investigation into the attack on Mr Lunney were carried out in the Irish border and also one at an address in the Buxton area of Derbyshire last Friday.
A man died during the Derbyshire Police raid, it is believed he had a heart attack.
The Independent Office for Police Conduct (IOPC) has launched an inquiry into the circumstances of the death.