Taoiseach Leo Varadkar has said that there cannot be an amnesty for those who committed crimes during the Troubles.
Speaking in the Dail on Wednesday Mr Varadkar said that the Irish government would not support an amnesty for the crimes, no matter who committed them.
He was speaking after Prime Minister Boris Johnson promised that if re-elected after the General Election, his party will introduce measures to support military personnel, veterans and their families.
Under the proposals, the Conservatives would amend the Human Rights Act so it does not apply to cases such as Troubles killings, which happened before it came into force in 2000.
Mr Varadkar said that while the PM's plan was not a complete amnesty it was something the Irish government was "concerned about".
He told TDs that he planned to raise the matter with the British Government.
UUP MLA and former Doug Beattie said that he believes the pledge is a ploy from Mr Johnson to gain votes from the veterans community in December's General Election.
"The problem is that if you bring in legislation on a statute of limitations or presumption before prosecution, the reality is that it will set a precedent in case law and will apply as well to terrorists," Mr Beattie said.
"It is actually a de facto amnesty and I wish they would just be honest. What they're trying to do is draw a line in the sand of prosecutions in Northern Ireland and that includes terrorists getting away scot-free for the perverse nature of the things that they did."
Mr Varadkar's deputy Simon Coveney also poured cold water on the proposal, saying the announcement was "worrying".
He said the Irish government had not been told or consulted about the plan.
“We have an agreement between both governments and the parties in Northern Ireland on how to progress, to manage very sensitive legacy issues, and to move a process of reconciliation forward," the Irish Foreign Minister said.
“That was the Stormont House Agreement and within that agreement there’s no amnesty for any one sector within Northern Ireland, or people who are involved in breaches of the law during the Troubles.
“I think it’s important in a process of reconciliation and legacy that it moves ahead in a way that’s consistent with what has been agreed."
The idea of such an amnesty has been floated over a number of years, with calls for its implementation rising after a decision earlier this year to charge one soldier, known as Soldier F, for his part in the death of two people on Bloody Sunday in Londonderry in 1972.
A leaked memo from March this year revealed that then PM Theresa May had ruled out the idea of a statute of limitations on historical prosecutions of military personnel who served during the Troubles in Northern Ireland.