The Otago University proctor says he fears someone may die in "sadistic" second-year initiations.
Last year, the university took disciplinary action against 17 students involved in the initiations, which reportedly saw people shaving their heads, stripping and skulling drinks until they vomited.
Out of those 17, it is understood that nine were excluded for one semester.
This year the proctor Dave Scott decided to take action.
In an email sent to the heads of the residential colleges, where many first years lived, Mr Scott warned of the dangers first year students had when heading into initiations the following year.
"Often there is a power imbalance, with guests being forced or coerced into dangerous, antisocial and often unlawful behaviour."
Mr Scott said that while most of the initiations were fairly tame, some just went too far and led to serious breaches of health, safety and the law.
He asked that hosts consider those three things when planning ceremonies.
"If you are the host: Remember your guests are human beings, they should be treated with dignity and respect.
"Consider any event you are planning, give thought to what is being proposed.
"Is the event unsafe, is it antisocial or unlawful? Are you applying coercion or pressuring your guests to participate in activities? Would your event hold up to scrutiny?"
Mr Scott also said students invited to events could decline if they felt their safety was in jeopardy.
"If you are a guest, the event has nothing to do with your tenancy agreement for 2019. You do not need to attend.
"If you chose to attend you can say no to any activity that you chose not to participate in."
Mr Scott would visit flats known for dangerous events to ensure students understood what behaviour was acceptable.