Irish Foreign Minister Charlie Flanagan has been challenged by the UUP’s Danny Kennedy to deliver what was promised to the Kingsmills families.
His plea comes after Monday’s inquest at which victims’ families learnt the Irish government have failed to hand over critical files.
It came on the same day BBC NI reported Mr Flanagan as saying “all responsible authorities” needed to support the rule of law.
In response to criticism of legacy inquiries by NI Secretary James Brokenshire, who said they focused “disproportionately” on state forces, the Irish foreign minister said: “There are no amnesties from prosecution provided for in the Good Friday Agreement or any subsequent agreements including Stormont House.
“The Irish government would not look favourably on any proposal to introduce such a measure – for state or non-state actors.
“The rule of law including the requirement for effective investigations of unlawful killings must be upheld by all responsible authorities.”
Mr Kennedy said Kingsmills was not an example of an “effective investigation upheld by all responsible authorities”.
The Ulster Unionist Party’s Assembly candidate for Newry and Armagh, said: “As someone who has spent literally decades helping to support the families of the 10 Protestant workmen murdered at Kingsmills in January 1976, I would say one thing to Mr Flanagan.
“I was present at a meeting with the Taoiseach Enda Kenny on March 26, 2015 when he gave an undertaking that the Irish government would co-operate fully with the coroner’s inquest into the killings.
“At the time I described the meeting as being ‘very constructive’.
“The taoiseach gave families and public representatives assurances that the Irish government will share all relevant documentation in relation to the Kingsmills atrocity with the Northern Ireland Coroner.
“I regret to say that we are now almost two years on, and yet the families are still waiting. It is high time the government which Mr Flanagan represents, kept its word and delivered what was promised to the Kingsmills families.”