At a planning and environment committee meeting, Cr John Bezett criticised the OUSA for announcing its intention to seek a judicial review into the university's decision to exclude several students for code of conduct breaches.
Cr Dave Cull criticised police, who, he said, "stood and watched it happen" when a toga parade descended into disorder in February, instead of using the liquor ban in place in the central city, and other methods, to quell the problem.
The University of Canterbury Engineering Students Society (Ensoc) met Dunedin Mayor Peter Chin, police, fire service and University of Otago representatives last Thursday to gauge feeling for an event this year, only to be told again they were not welcome in the city.
The committee voted to support a temporary liquor ban for North Dunedin first introduced in 2007.
The ban was originally put in place following lobbying by police to give officers powers to control partying after the annual rally in which participants drive from Christchurch to Dunedin and back in vehicles valued at less than $500.
The rally has regularly sparked drunken disorder.
Cr Bezett said he was "disappointed" with OUSA, which he said had promised to help police and the university identify people responsible for disorder but "at the first opportunity" had instead supported those students.
Cr Cull told the meeting he supported the ban, but had reservations.
"It's all very well the police asking for this.
Are they going to enforce it?"After the meeting, he said a North Dunedin retailer had warned police, both by telephone and by visiting the police station before the toga parade, that students were gathering with missiles, and there was going to be trouble.
It was a chance for police to be pro-active, but that had not happened, and Cr Cull said police should have used the liquor ban and "other pro-active powers".
Dunedin-Clutha area commander Inspector Dave Campbell said there was a misunderstanding about the start time of the toga parade, and as a result police had only been briefed at the station when trouble started.
Police would "most certainly" use the ban if necessary for the Undie 500, although it alone would not solve the problem.
"It's not the answer.
"It's just another tool in the tool kit," Insp Campbell said.
