Police are advising people to be alert and vigilant, but not alarmed, as they investigate an online threat of violence at Otago University today.

A post on an online site known for anonymous posts, makes reference to the Virginia Tech shooting in the United States.

The threat was posted online on Monday night.

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A number of students have responded, saying they'll be avoiding the campus today.

Acting Area Commander Inspector Mel Aitken reports a high tech crime team is helping Dunedin police authenticate the threat.

"We do understand that a threat of this nature could be concerning to some people. Police, University of Otago and campus watch staff will be available to speak with anybody who has any concerns."

Aitken said police take any threat seriously while its source and authenticity is being assessed.

"We;re also mindful of the possibility of copycat threats following high profile events that occur overseas. We'll deal firmly with any individuals associated with any such copycat threats."

Editor of Otago University's student magazine Critic, Josie Cochrane, said students are concerned.

"There's lots of chat going on about it ... most people are saying this is pretty sick, what he's doing - if it's a joke or whether he's serious".

Cochrane said she still expects there will be a fairly good turnout on campus despite the threat. 

"Students, if they can have a reason to stay at home, quite often they'll find one. But I think in general it will be a pretty good turn out at Uni today - with exams so close most people don't want to miss the revision."