Otago Corrections Facility prison director Dave Miller said staff instructed the man to return to his cell due to his ‘‘abusive and threatening behaviour towards staff’’ about 10.45am today.
The man ‘‘actively resisted’’ staff trying to move him and bit one on the thumb as he reached his cell, Mr Miller said.
The staff member was seen by a medical team before being sent home, and was being provided with support.
The prisoner has been placed on directed segregation.
Assaults on staff were unacceptable, and Corrections Officers did an exceptional job to quickly secure the prisoner in his cell and assist the wounded staff member, Mr Miller said.
Corrections officers came to work to keep New Zealanders safe and do an exceptional and brave job - in often very challenging circumstances, he said.
‘‘Every assault on a member of our staff is taken seriously and any prisoner who resorts to violence will be held to account."
A police spokeswoman said the assault had been reported and they were making inquiries.
