The Irish deputy leader has said an announcement by the Prime Minister pledging a law change to protect armed forces veterans who served in Northern Ireland is worrying.

The Conservative pledge announced on Monday morning says it will prevent veterans facing “vexatious” legal action over historical allegations by changing the law.

Making the announcement, Boris Johnson told veterans: “We will always support you.”

Veterans minister Johnny Mercer said under the proposals, the Human Rights Act “will be amended to specify that it doesn’t apply to issues – including NI – that took place before the Act came into force in October 2000”.

Simon Coveney, speaking at the Foreign Affairs Council in Brussels, said the Irish government had not been told or consulted about the announcement, which would be in contravention of the 2014 Stormont House Agreement, and it would be opposed to it.

“That is a worry, perhaps this is just a part of an election campaign,” Mr Coveney said.

“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.

“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.

“Of course, we’ve not seen any detail in any election manifestos on the issue yet, but from our perspective we have an agreed approach, it’s in the Stormont House Agreement and I hope that’s respected.”

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.

“It’s true that this issue has been controversial and a difficult issue for quite some time, that’s no secret,” Mr Coveney added.

“The previous secretary of state Karen Bradley was put under pressure on this issue, in the House of Commons the current Secretary of State has also been asked questions on this issue, so there are clearly those advocating for a statute of limitations or amnesty for the armed forces in Northern Ireland during the Troubles, but that’s not consistent with what has been agreed.

“The agreement should be setting the parameters for the way forward, that’s the basis on which everyone expects us to move forward.”

Human rights groups have also voiced their concern at the mooted changes.

Grainne Teggart, Amnesty International’s Northern Ireland campaign manager, said: “All victims have the right to an independent investigation – that is a cornerstone of the rule of law throughout the world.”