The Fine Gael leader, Mr John Bruton, has called on the Taoiseach to order a Garda investigation into State files relating to the 1969 arms crisis which appear to be missing.
Mr Bruton wrote to Mr Ahern yesterday demanding a Garda inquiry into the missing papers on the arms smuggling scandal which led to the sacking of Mr Charles Haughey and Mr Neil Blaney from government in 1970.
Last night a brother of the late Mr Blaney, the independent TD for Donegal North East, Mr Harry Blaney, also called on Mr Ahern to carry out "a full and detailed inquiry" into the matter.
Mr Blaney said people connected with the arms crisis were still alive. They could be questioned about their knowledge of the possible whereabouts of the files.
He said it would not surprise him that papers were believed to be missing.
"It probably did not suit certain people to have them shown at this time. Somebody is clearly trying to hide something," he said.
His late brother had told him the full story of what happened at the time and of decisions taken by cabinet at the time, which never came out.
"I will be trying to talk to the Taoiseach about this matter as soon as possible. I would dearly love to see every last paper relating to the time produced. That should shed some light on what happened. The full truth never came out," he said.
The papers from August 1969 were not released to the National Archives under the 30-year rule which applies to official documents.
Mr Bruton said in a statement yesterday he would be raising the matter in the Dail when it resumed at the end of the month. He confirmed he had written to Mr Ahern setting out his concerns.
He said the matter of the crucial missing files was a task for the Taoiseach and the Garda.
"As the recent Ansbacher leaks show that the Garda will not investigate without an invitation from the Government, I call on the Taoiseach to initiate an inquiry."
A Government spokesman said it had yet to be established whether there were any State papers missing for the period concerned.
"To date the National Archives Office has not informed the secretary-general of the Department [of the Taoiseach] or the senior official dealing with these papers about the possibility that the papers are missing."
He said the Department of the Taoiseach, in conjunction with the National Archives Office, would seek to establish over the coming days whether there were State papers missing or if there was some other explanation for their absence.
He said until it was established that papers were missing it was premature to talk about a Garda investigation.
Mr Bruton said last night the matter of the missing files must have come to the attention of the Taoiseach's office in the last 12 months.
"It appears to me that somebody censored the file. From January of 1999, work would have been under way on files for release this week.
"The main file on the main topic of political and public interest from 1969 is missing. Somebody in the Taoiseach's Department would have alerted the secretary of the Department that it was missing.
"If the Taoiseach himself was not aware of the significance one of his advisers would have been."
Mr Bruton said many of those involved in the events of 1969 were still alive and could have been contacted about the missing files.
"It is not a trivial matter that a major archive of State is missing. This is a hugely important file," he said.
The destruction or removal of key State papers for August 1969 from the Taoiseach's office prior to their scheduled hand-over to the National Archives was a criminal offence.
"If it happened someone was trying to rewrite history and cover something up. Only a very small number of people would have had the access or power necessary to remove or destroy these files, and those in charge of them since 1969 are identifiable individuals.
"Detecting the culprits should not be an excessively difficult task, but it is not one that can be completed by the National Archives Advisory Council or any other voluntary body."
The chairwoman of the National Archives Advisory Council, Ms Margaret MacCurtain, told the Sunday Tribune the council had become aware of a gap for August 1969 and intended to investigate it with the Department of the Taoiseach.