Security guards at Christchurch Hospital will be given stab-proof vests to protect themselves from attacks by patients.
The hospital says in a four-month trial the vests protected against blows to the body, kicks, punches, being pushed against walls and some weapons.
The Canterbury District Health Board says it is unfortunate that the vests are necessary, but staff need protection.
The DHB's general manager corporate services, Murray Dickson, says in the past year there were 527 assaults on staff.
Four assaults were in the emergency department, about 69 in the area of elder care, while the majority occurred in the mental health sector, he says.
Security guards at Hillmorton Hospital, a mental health facility in Christchurch, have also been issued with the vests following the trial.
Waitemata DHB has also confirmed it has also ordered the vests and expects them to arrive within a month.