An elderly Marist brother and former school principal who sexually assaulted five boys in regional Victoria while giving them "sports massages" will serve nine months in jail.

But a spokesman for child sex abuse victims has slammed the sentence as too lenient, calling it tokenistic and "appalling".

Gerard McNamara outside court in July. Credit:AAP

Gerard McNamara, 80, molested the aspiring athletes at St Paul's Catholic College in Traralgon between 1970 and 1975, including one boy he abused some 30 times.

As sports master and principal of the school, McNamara usually assaulted his victims on a massage bench in a sports shed after they had suffered injuries during athletics.