A new report on sentencing has found that judges in manslaughter cases tend to be more lenient if drink and drugs are involved, even though intoxication is not a defence in law or a mitigating factor.
The report analysed sentences in manslaughter cases over five years between 2007 and 2012.
It was carried out by the Irish Sentencing Information System.
The report also shows that more than 80% of those convicted of manslaughter in the cases studied received sentences of nine years in prison or less.
Many of those who received lower sentences were teenagers or young adults.
However, the report highlights one case where a man was sentenced to three years for pulling a victim to the ground and stamping on her head as apparently "rather lenient".
Of the 42 cases analysed, eight convicted killers received suspended sentences or less than four years in prison.
Another 26 convicted killers were sentenced to between five and nine years in prison, while eight received ten years or more in prison.
The report states that "perhaps further guidance from the Court of Criminal Appeal regarding categories of manslaughter might assist to clarify any ostensible discrepancies".