Three Corrections Department staff have been assaulted this afternoon by three prisoners at the Otago Corrections Facility.
But the Corrections Association says all of the staff who were assaulted are fine.
The staff members were assessed by health staff and one required further medical treatment for non-life threatening injuries.
The department said the injuries were not critical and the police are investigating.
The facility was in lock down, but it is now back up and running as usual.
The association's president, Alan Whitley, said these types of events happened from time to time and was an unfortunate side effect of what prisoners do.
"Three staff have received some injuries after a scuffle with some prisoners in Otago this afternoon, one was knocked about a little bit and managed to finish his shift, the other two had some off-site medical attention, but they are all right at this point in time."