The Government has "serious concerns" about Britain's proposed legacy Bill and "cannot support it in its current form," Minister for Foreign Affairs Simon Coveney warned on Wednesday night.
Mr Coveney said these concerns included the powers of a new truth recovery commission and compliance with international human rights obligations, including article two of the European Convention on Human Rights.
Mr Coveney said it was “disappointing” London had chosen to “unilaterally introduce legislation” but Dublin would continue to engage and would speak to political parties and victims groups.
On Wednesday, groups which between them work with more than 4,000 people bereaved by the Troubles said they will advise non-engagement with the proposed legacy body.
Relatives for Justice (RFJ) and the Pat Finucane Centre (PFC) said their "strong advice" to families would be that they should not participate in any of the measures put forward in the legislation introduced on Tuesday.
The Northern Ireland Troubles (Legacy and Reconciliation) Bill will create a new truth recovery body – the Independent Commission for Reconciliation and Information Recovery (ICRIR) – which will offer immunity from prosecution to perpetrators who co-operate with its inquiries.
It will take over responsibility for all Troubles inquiries and other avenues of criminal and civil investigation and inquests will be closed down.
The plans have been widely condemned, including by the North's five main political parties, victims and human rights groups, the Irish Government and other parties in Ireland and in Britain.
Paul O’Connor from the PFC and its sister organisation, Justice for the Forgotten, said the proposals “contain nothing for families bereaved in the conflict” and they could have “no confidence at all in these proposals, in which they would have no powers of legal scrutiny and which would provide no accountability.
“We would also hope that the Irish Government would have nothing to do with this,” he said.
"The British government have shut down the courts because the courts can deliver," said Mark Thompson from RFJ. "They are shutting everything down and putting this in its place and that's why you would have nothing to do with it because it's not going to deliver anything for families, it's perpetrator-centred, and it's anti-victim."
A spokesman from the Northern Ireland Office (NIO) said the legislation would ensure an "effective information recovery process, underpinned by robust and independent investigations, to provide answers for families, deliver on commitments to those who served in Northern Ireland, and help society to look forward.
“The legislation will ensure that legacy issues are addressed comprehensively and fairly, and in a way that supports information recovery and reconciliation, complies fully with international human rights obligations and responds to the needs of victims and survivors, and society as a whole.”
On Wednesday papers were lodged in at least 100 legacy cases in an attempt to avoid the block on new civil cases.
Paddy Murray of Ó Muirigh Solicitors in Belfast, which lodged between 15 and 20 cases, said there was a "very real concern" that the door had been closed already.
“It’s horrendous that any government would just close down private law remedies such as civil actions at a whim, I haven’t seen it in any other examples or any other truth processes like this,” he said.
The proposed ending of inquests, he said, was of “great concern” to many families. “It’s no accident that we finally have a legal tool which is effective and is delivering for families and the British government are closing it down.”