The Irish Government is in "direct contact" with the coroner conducting the Kingsmill inquest, foreign affairs minister Charlie Flanagan said.
The Ulster Unionists have criticised the amount of information provided by Dublin about the 1976 IRA murder of 10 Protestant workmen in South Armagh.
UUP chief negotiator Tom Elliott said the level of Irish transparency had not come close to what the UK was planning to deliver on legacy cases.
Mr Flanagan said: "The Irish authorities' co-operation with the Northern Ireland coroner is part of an ongoing legal process and they remain in ongoing direct contact with the coroner to identify ways in which further support or assistance can be given to the inquest, in accordance with the law."
He said the Government was strongly committed to the early establishment of and full support for the comprehensive framework set out under the Stormont House Agreement to deal with the legacy of the past.
He added: "In respect of the Northern Ireland coroner's inquest into the murders at Kingsmill, the Government has been very clear about its willingness to assist the coroner in accordance with the law and has put in place explicit measures to facilitate the transfer of material."
Judge Brian Sherrard is holding the new inquest.
Mr Flanagan added: "The transfers of relevant material to the coroner has already taken place."