The manslaughter of a Waikato prison guard will be the subject of a coronial inquest.

Hamilton coroner Gordon Matenga has decided an inquest will be held into the death of Spring Hill prison guard, Jason Palmer, 33, a former United States marine, who died after he was attacked by inmate Latu Kepa in May.

Kepu, 22, was jailed for six years and four months after pleading guilty to Mr Palmer's manslaughter.

He admitted punching Mr Palmer in the mouth. Mr Palmer fell back and hit his head on the concrete floor. He never regained consciousness and died in Auckland's Middlemore Hospital from a brain injury.

Mr Matenga's office said a date and place for the inquest had yet to be determined.

"Some issues had been raised and he feels an inquest is necessary and will take place," said a spokeswoman for Mr Matenga.