Eleanor Butterworth, Wellington Rape Crisis agency manager, alleged at least one of Otago's student association officers was a "Rack" page administrator, or had shared content on the page.
"How are victims meant to get help if they can't trust people in positions of power to take this issue seriously?" Ms Butterworth said.
The Otago University Students' Association was holding an unscheduled meeting this afternoon and nobody was available to respond to the claim.
An Otago University spokeswoman said the institute had "an ethical behaviour policy" which emphasised "dignity and respect."
In a later statement, a spokesman said the University's proctor was now investigating a complaint relating to the deleted Facebook group.
Otago University advised anyone with concerns about the issue to contact the proctor's office or a member of the University's ethical behaviour network.
Fiona McNamara of the Sexual Abuse Prevention Network said sexual abuse prevention education was needed in all schools and tertiary institutions.
"If universities and schools create a space in which to talk openly about these issues, they demonstrate to students that such incidents are serious and should not occur."
Ms McNamara said sharing sexual photos of somebody taken without the photographed person's consent was despicable.
"We live in a rape culture where sharing explicit photographs without consent is seen by many as normal behaviour."
Ms McNamara said some mainstream New Zealand media outlets had posted leaked celebrity nude photographs and by doing so also fostered "rape culture".
The new Minister for Women, Louise Upston, was being briefed on the Facebook groups this afternoon.
Labour women's affairs spokeswoman Sue Moroney said the Facebook groups showed little had changed since last year's Roastbusters scandal.
Then, explicit content relating to sexual activity with intoxicated or underage girls was shared on Facebook.
"This is exposing a really ugly underbelly of sexism," Ms Moroney said.
She said people and groups in influential positions needed to spearhead a cultural change needed to overcome misogynistic attitudes.
Critics of the Skank Central Christchurch page earlier this week included Mark Longley, whose daughter Emily was murdered in 2011.