On Tuesday, a Dunedin student had to be taken to hospital with a "decent cut" after a bottle was thrown at his head on the first night of Flo-Week parties.
Senior Sergeant Craig Dinnissen said the students were mostly well behaved and there were "no major issues", but there were some problems associated with glass bottles.
Otago University Students’ Association president Daniel Leamy said while such behaviour was disappointing, it was displayed by "less than 1%" of the student cohort.
"It comes down to the fact there’s 20,000 students in Dunedin, and it’s one bad egg in that situation that gets picked up on.
"But the reality is, if you go out on to Castle St, or not just Castle St, if you go out in North Dunedin in the student quarter, the vast majority of students are enjoying their time in a smart, responsible way.
"It is just that there will always be one or two people out there who ruin it for everyone else."
The campaign to switch to cans had proved successful in the past, Mr Leamy said.
"We run it through posters. We run it through screens. We have it across all the social channels. And it has been adopted by police, together with the Don’t Be a Dick campaign. And we obviously make it available to various retailers."
Mr Leamy hoped to get more feedback from students about the campaign.
"But the vast majority of students drink out of cans, which is more sustainable, because they’re not ending up getting smashed. Yeah, it’s just easier and less mess. I do think the message is getting across."
