The first night last year - in which 13 pairs of people from the university community faced off against one another - generated about $28,000, participants being able to pick a charity each to raise money for.
OUSA president James Heath said this year's fight tied into one of his top priorities, which was encouraging physical health and promoting better mental health.
"It's responding to firstly what the students want. Last year, it was incredibly successful."
The fight will be held on July 12, and participants would have 12 weeks, two more weeks than last year, to get into shape.
A University of Otago spokeswoman did not comment when asked whether it had any views on the boxing match.
Already about 22 people had registered for the fight night, 24 hours after registrations opened. The fight, sanctioned by Pro-Box NZ, will be held in the union hall, and spectators are encouraged to "get glammed up" for the night.
So far no-one from the OUSA executive itself had signed up to get into the ring this year, however, that could change, Mr Heath said.
OUSA events co-ordinator Scotty Godsall said tickets would go on sale towards the end of May, with 350 spots in the audience available. The first six weeks of the "boot camp" leading up to the fight would be a selection process, in which about 24 fighters would be picked - people being matched on weight, age, skill level and gender.
Mr Godsall said the emphasis from both OUSA and himself was on health and safety, and the wellbeing of the fighters was the top priority.
For some people, getting physically and mentally in shape for the fight was one of the best things they had ever done, and a "massive journey", Mr Godsall said.
NZ Fight and Fitness would train all the fighters, who would be under some of New Zealand's top trainers, Mr Godsall said.
Mr Heath said there would be regular medical checks for all of the participants, who would be fight wearing 18 ounce gloves.