A chaplain at Taranaki Base Hospital is in a comfortable condition after being stabbed in the hospital's chapel.
The 65-year-old man received minor cuts to an arm and face, and bruising to his head, after being set upon about 8.40am on Thursday.
New Plymouth police said the chaplain was in his office when a man approached him and demanded money from the collection.
Sergeant Bruce Irvine said it appeared the man was attacked with a Stanley knife or similar tool, and hit over the head with a small wooden baton.
Police described the alleged attacker as a male Caucasian aged between 20 and 25 years and about 1.75m tall. He was wearing a black hoodie, black track pants with white stripes and black fingerless gloves, and has a distinctive star or sun ray tattoo over his left eye.
Mr Irvine warned that the offender is dangerous and should not be approached.