Separate CSO figures show a decrease in the number of burglaries and murders
Around 17% of crimes reported to gardaí last year were not recorded on Pulse, the force’s database system, new figures reveal.
Analysis by the Central Statistics Office (CSO) has identified a number of problems with the recording of crime statistics.
Concerns over the quality of crime data were first flagged by a Garda Inspectorate report in 2014.
The CSO stopped releasing crime figures for a period last year, following its own review, but resumed in June 2015.
Among the other findings published today are that:
Speaking this afternoon, Sinn Féin justice spokesperson Jonathan O'Brien called on garda management to address concerns raised in the review.
"It important that An Garda Síochána outlines the reasons for these issues so that the public can have confidence in the published crime figures," he said.
"It is also important because these figures will have an influence when it comes to the allocation of resources.
"We will be calling on the Minister for Justice to request that Garda Síochána address this matter as soon as possible."
The figures bring into question separate CSO statistics released this morning showing drops in a number of crime categories.
Burglaries fell by 26% in the 12 months up to the end of June 2016, while murder and manslaughter offences decreased by 18%.
Fraud, deception and related offences were also less frequent, down 9%.
There was almost no change in the level of drug crime, but kidnapping and related offences were up by 2.9%.
Sexual offences and assault causing harm also rose, by 13% and 7% respectively.
Offences against government, justice procedures and organisation of crime grew by 12%.