Part of Mokoia Dr was cordoned off for more than an hour while police searched the buildings and surrounding shrubbery.
About 5.30pm, small groups of four or five people were allowed back into the building to gather their personal items and were advised to go home for the night.
Professional cookery students were told they could continue working once they were back inside.
First-year professional cookery student Dylan Kelly said they were told to evacuate about 5pm.
Staff and students were evacuated from Waiariki Institute of Technology's Rotorua campus while police investigated a threat. Photo / Ben Fraser
"Well we figured it wasn't a shooter because they would have kept us inside and when walking past the reception area they told us to make sure none of our digital devices were on."
Mr Kelly said it was "freaky that something like this is happening in New Zealand".
"You think something like this only happens overseas, not in New Zealand.
"There are some loose units around and you never know what somebody is capable of. It is understandable that they would evacuate the whole school with so many people on campus."