The imposition last week of a suspended sentence on a convicted rapist "runs counter" to existing legal practice, according to a leading authority on criminal law.
Mr Tom O'Malley, a law lecturer at NUI Galway, described the sentence handed down by Mr Justice Dan Herbert as an "aberration" that obscured the fact that the sentencing of rapists is "uniformly severe".
Mr O'Malley, author of the book Sentence Law and Practice, said: "The average sentence for rape is between seven and eight years, and it's only in the rarest of circumstances that people don't end up going to prison.
"Parts of this judgment appear to run counter to the 1988 Supreme Court case (which laid down guidelines for rape sentencing policy)."
In his ruling to the Central Criminal Court on Friday, Mr Justice Herbert said "no actual injury was inflicted on the victim other than the rape". There was "only one" aggravating factor in the rape - the rapist had threatened to kill the victim - and several mitigating factors. The case was much less serious than "serious rape cases" in which sentences of up to 18 years had been passed.
In 1988, the then Chief Justice, Mr Justice Finlay, said the appropriate sentence for rape was a substantial immediate period of detention or imprisonment.
