The UK government has put itself on a collision course with politicians in Belfast and Dublin and drawn sharp criticism from victims and rights groups after unveiling details of an effective amnesty for crimes committed during Northern Ireland’s Troubles.

Brandon Lewis, Northern Ireland secretary, confirmed on Wednesday the plan, which had been widely leaked, to legislate to ban all prosecutions related to crimes committed during the 30 years of conflict in the region that ended with the 1998 Good Friday Agreement. All civil actions and inquests related to the troubles may also be stopped.

Lewis told the House of Commons that prosecutions for crimes that typically happened more than 30 years ago were becoming increasingly difficult and the process of pursuing them led to “pain, suffering and disappointment” for families who had lost loved ones.

“We know that the prospect of an end of criminal prosecutions will be difficult for some to accept and this is not a position that we take lightly . . . It is a painful recognition of the reality of where we are,” he said.

Families have spent decades fighting for justice and answers in relation to the deaths of more than 3,600 people during the Troubles. Their attempts have mostly been futile, despite a political commitment to investigate historical crimes and apply the rule of law as part of the Stormont House Agreement underpinning Northern Ireland’s current government.

Earlier this month prosecutors abandoned the only charges brought over the Bloody Sunday deaths of 13 civilians at the hands of British soldiers in Londonderry, also known as Derry, in 1972.

Sir Jeffrey Donaldson, who heads the Democratic Unionist party, Northern Ireland’s biggest political party, said Lewis’ proposals were “totally unacceptable and will be rejected by everyone in Northern Ireland who stands for justice and the rule of law”. The DUP objected, he said, to the principle of soldiers and police officers being treated in the same way as terrorists.

Sinn Féin, a nationalist party and the second biggest force in Stormont, described the measures as an “amnesty for British soldiers who went into the streets and gunned down innocent civilians in Derry, Ballymurphy and beyond”.

“It’s an act of absolute bad faith on behalf of the British government,” Mary Lou McDonald, Sinn Féin leader, said as she called on Micheál Martin, Ireland’s Taoiseach, to intervene.

Martin said in the Irish parliament that “a unilateral move away from the Stormont House Agreement and the introduction of what amounts to a general amnesty . . . is not the right way to go”.

“The British government may be setting out its position but our position as an Irish government, shared with all of the political parties in the North and all of the victims’ groups, remains consistent with that of the Stormont House Agreement.”

Grainne Teggart, Amnesty International’s Northern Ireland campaign manager, said London was “showing an appalling and offensive disregard for victims; grossly dismissing their suffering and rights to truth, justice and accountability”.

Condemnation from victims and their representatives was widespread. Michael O’Hare, whose 12-year-old sister Majella was shot dead by a British soldier in 1976, said the proposals were an “utter and unacceptable betrayal”.

Wave Trauma, the largest community victims’ group in Northern Ireland, sent Boris Johnson, UK prime minister, an open letter on July 5, warning him that an amnesty “will not aid reconciliation. It will cause anguish and bitterness that will bleed into subsequent generations.”

The plans also include a new independent body for recovery and provision of information about Troubles-related deaths and serious injuries, as well as a “major oral history initiative”, which will be used to create reports on the circumstances of individuals’ deaths and serious injuries.

Lewis argued these were “more likely to give families some sense of justice through acknowledgment, accountability and restorative means”.