A Whanganui prison officer had part of his ear bitten off and another needed staples and stitches to a serious head wound after an inmate they were transporting to hospital slipped out of his high-security handcuffs and attacked them.
It is understood he used the cuffs as a weapon during the violent incident at Whanganui Hospital late on Sunday night.
NZME has learnt that the two prison officers had escorted the inmate from prison to the hospital for treatment.
As they were getting him out of the van he allegedly turned on them.
A source said he had managed to get his hands out of the cuffs placed on him at the prison and use them to wound the officers.
One officer had part of his ear bitten off during the attack and the other needed a number of stitches and medical staples to close a gash to his head.
Police are investigating the incident and say it's likely the inmate will be charged.
Corrections acting Deputy National Commissioner Neil Beales confirmed the incident, however, as it was under investigation, he could not comment on the specifics.
"On Sunday evening a prisoner was escorted to Whanganui Hospital at approximately 11pm, following assessment by an on-site prison nurse," he said.
"On arrival at the hospital, the prisoner assaulted the staff who were escorting him.
"The staff responded immediately to restrain the prisoner with the assistance of hospital security, and police were called.
"The Corrections officers showed immense courage to bring the situation under control quickly and safely.
"In doing so they sustained injuries to their faces, heads and arms and one officer has a serious ear injury."
Beales said both officers were treated at hospital and were discharged soon after.