A man stabbed his associate in the stomach at Taranaki Base Hospital this afternoon due to an "ongoing dispute'', police say.
Armed police went to the hospital shortly after midday when frightened hospital staff alerted them to the incident.
Detective Senior Sergeant Grant Coward said the alleged knifeman, 45, was known to the victim, 39.
The accused was compliant with police when they arrived and arrested him, police say.
He was charged with wounding with intent to cause grievous bodily harm and will appear in New Plymouth District Court tomorrow.
The victim was in a stable condition in the hospital, where he was being treated for a single stab wound.
Police had not located the weapon, Mr Coward said.
Police appealed for anyone who witnessed the incident to come forward.