A garda review of 41 homicide investigations between 2013 and 2015 has found that at least one issue arose in 28 of the cases.

The Garda Homicide Investigation Review Team identified issues around data quality and misclassification.

Twelve of the deaths were reclassified as a result of the review, however the report found that the issues identified did not have an impact on the outcome of 40 of the investigations.

One of the investigations remains live and was not included in the final report.

The outgoing chairperson of the Policing Authority, Josephine Feehily, described the findings as "worrying" and said An Garda Síochána must implement the report's 21 recommendations fully and quickly.

The Garda Commissioner said that five of these, which relate to training, the prioritisation of taking statements from key and vulnerable witnesses, and exhibit management, have already been completed.

Commissioner Drew Harris also said the other 16 will be resolved by the roll out of a PULSE fix, a new investigation management system, legal issues and the input of other stakeholders.