Palmerston North Hospital is restricting the number of visitors following the closure of a third ward this week due to norovirus.
Three suspected cases of the highly contagious gastric illness in a rehabilitation ward on Wednesday forced the hospital to stop patient admissions to the ward and elective surgery was postponed.
Two wards were closed last week in an attempt to contain the outbreak of the virus.
Relatives of patients are being asked not to visit unless it is absolutely necessary, and to use hand hygiene stations positioned around the hospital.
By Saturday, 62 staff and 36 patients had caught the virus.