"Corrections manages some of New Zealand's most difficult and challenging citizens, violence is always a risk as many offenders resort to violent behaviour as a means of resolving issues and of expressing themselves.
"Prisoners can be volatile and unpredictable and many have long histories of antisocial behaviour.
"The Department will not tolerate prisoners using violence against staff or other prisoners, and when this does occur the prisoners involved will be held to account for their actions."
Police said the accused man was known to Ihaka, who suffered multiple blunt force injuries including broken bones in the alleged assault at a house in Truman Rd, Bryndwr on July 3.
Ihaka was transported to the accident and emergency department at Christchurch Hospital after being found unconscious and with unexplained injuries, and died shortly afterwards.
More than 42 people were interviewed by officers working on the homicide investigation codenamed Operation Truman.
