The section of An Garda Síochána which oversees the recording of DNA samples does not have adequate staff, according to the garda's internal watchdog.
The Garda Professional Standards Unit has identified a number of issues in how the National Forensic Coordination Office manages and monitors the recording of DNA material.
It found current staffing levels within the section are inadequate.
In its annual report, the oversight body also said a quarter of gardaí are taking DNA samples without being properly trained. The report found many officers rely on a "how to" video on the garda internet service to assist them.
GPSU interviewed gardai across 12 divisions and found 81% were involved in the taking of DNA samples, however, only 55% said they had received training on the taking, retention and destruction of DNA samples.
It found "the lack of appropriate staffing levels is an organisational concern that needs urgent attention".
The watchdog said only 67% of DNA samples taken during detentions were recorded on custody records and that 92% of reports matching a profile to a crime were acted on by gardaí.
It also found a "lack of oversight and governance" in relation to the submission of samples into the DNA database operated by Forensic Science Ireland.
It said the laws around DNA are not being fully utilised in part because of a lack of awareness and training.
Among 38 specific recommendations it proposed the introduction of a "robust system" to manage the issues.
The NFCO was established four years ago as part of reforms which included the creation of the national DNA database system.
A garda spokesperson said the report is being considered by Garda Commissioner Drew Harris and his senior leadership team.
The General Secretary of the Garda Representative Association has said it is critical that the National Forensic Coordination Office was "fully resourced with adequate facilities."
"DNA is a modern technique essential to crime investigation and the location of missing persons. Any inadequacy in resourcing leads to an impact on the service provided," Pat Ennis said.
The GRA said the training of officers in DNA testing was better suited to classroom-based learning than online tutorials.
"This is an ongoing problem in An Garda Síochána. Large volumes of material are dumped onto the garda portel for members to read," Mr Ennis said.
The association called on Garda Commissioner, Drew Harris, to act upon the recommendations in the GPSU audit.