The Corrections Department says Wednesday's knifing in the back of a community work corrections van is the first of its kind on record.
A 37-year-old man was hospitalised with neck injuries after he was attacked with a pocket knife while in the back of a van in the Hutt Valley.
General manager of probation and psychological services, Katrina Casey, says the department will review the circumstances of the attack once police complete their investigation.
Ms Casey says people doing community work are not in custody and live and work in society on a daily basis.
Passengers in the van had worked with tools all day without any sign of problems.
