The students from six University of Otago residential colleges will be putting in more than 2000 hours in total as part of the scheme.
Weeding, working tills, painting and bark-laying are among the activities planned for students across the whole week.
University volunteer centre co-ordinator Sze-En Watts, who was helping run the scheme, said students were increasingly getting involved in volunteering.
This trend was helping change some of the unfair stereotypes the student population had been labelled with, Mrs Watts said.
"There are definitely stories in the media which are very exciting, but they are not a really true representation of the majority of students."
Several colleges volunteered during O-Week last year, but this year would be the biggest volunteering effort yet.
Aquinas College residential assistant Finn Shewell said volunteering was rewarding and had the added bonus of looking good on your CV.
It was also a good way to get to know more of Dunedin and to make new friends, Mr Shewell said. It also went "leaps and bounds" towards changing negative perceptions of students.
● Other residential colleges run their own volunteering programmes.
