The Road Safety Authority has asked Garda management to provide written reassurance as to the accuracy of the official road fatality statistics.
Despite making the request last year, gardaí have informed the RSA that it is unable to provide the reassurances sought, while a review of homicide figures is underway.
In a letter seen by RTÉ's This Week programme, RSA Chief Moyah Murdoch requested specific and detailed information from Garda authorities to enable the RSA to carry out a verification exercise on the official fatality data.
Her request follows concerns which were raised by the Central Statistics Office in relation to the reporting of homicide figures.
The letter shows that Ms Murdoch said she believed it was critical to undertake a verification exercise "to reassure the public that the official fatality statistics published by the RSA are accurate".
The letter was written to former commissioner Nóirín O'Sullivan in July 2017, but the RSA received no response to the request.
A month ago the letter was re-submitted, this time to Assistant Commissioner David Sheahan, who is in charge of Roads Policing in the force.
In it, Ms Murdoch notes concerns raised by the CSO in relation to the reporting of homicide figures, and issues in relation to the reporting of dangerous driving causing death incidents.
She seeks reassurance from garda management that the current procedure for recording road traffic crashes is consistently applied by gardaí.
She asks for confirmation "that all dangerous driving causing death incidents that have occurred over the period 2003-2016 are also correctly classified as fatal road traffic crashes".
In the letter Ms Murdoch also seeks confirmation that any person or persons seriously injured in a dangerous driving causing death incident, that these persons are recorded in the correspondent RTC incident.
In reply, Assistant Commissioner David Sheahan told Ms Murdoch that he was unable to provide her with written reassurance pending the outcome of a comprehensive review of homicide figures "which is still a number of months away from being completed".
The Road Safety Authority said it has been given verbal assurances as to the validity of the road death figures, and it accepts the "Bona Fides of the gardaí in relation to this matter".
However the Authority said it remains in contact with the Garda Information Services Centre to validate figures, and also monitors media reporting and garda press office alerts on road fatalities to cross reference and check up on figures.
