The chairman of the Smithwick Tribunal has written to the Oireachtas seeking to extend the deadline for the inquiry's final report until October.
The tribunal is inquiring into allegations of Garda or State collusion in the IRA ambush of two senior RUC officers, Chief Supt Harry Breen and Supt Bob Buchanan, who were killed near a Border crossing in 1989.
Chaired by former district court president Judge Peter Smithwick, the tribunal was established in 2005. It began public hearings in June of last year and was initially due to issue its final report last November.
The tribunal was granted an initial six-month extension to its deadline by Minister for Justice Alan Shatter in October.
In a letter sent to the Clerk of the Dáil Kieran Coughlan last week and subsequently lodged in the Oirachtas library, Judge Smithwick said he was seeking an extension until the end of October to hear further evidence from witnesses and write his final report.
He said that Owen Corrigan, a former Garda sergeant represented at the tribunal, had been due to commence his evidence last week but applied for a deferral on medical grounds. The request was granted, he said.
Judge Smithwick said it would take about three months to write his report and that the printing and editing process would take a further month. He said there would be a significant reduction in running costs once the public hearings concluded.
The tribunal has heard evidence from 190 witnesses, sat for almost 100 days and cost more than €8 million to date.
Judge Smithwick and Mr Shatter previously clashed when a deadline was initially set for the tribunal to complete its hearings.
Judge Smithwick accused the Minister of a “wholly inappropriate” attempt to “interfere with the independence” of the inquiry.