Southern District Health Board hospital staff have the cleanest hands in the country.
The board was first among the 20 boards in the last hand-washing audit, hand-washing having become a national target in a bid to reduce hospital-acquired infections in New Zealand hospitals.
Director of quality Tina Gilbertson said the board worked hard to change the culture in its hospitals, and provided constant data to wards about how they were faring.
Measuring hand-washing is complex.
The standard was high, and it was not realistic in every situation, Ms Gilbertson said.
To comply, staff had to wash their hands after five ''moments'' of patient contact - before touching a patient; before a procedure; after a procedure; after touching a patient; and after touching a patient's surroundings.
Southern had a compliance rate of 85% in the three months to June 30.
The poorest performing board was Tairawhiti, on 72%.
The national average was 80%.
Ms Gilbertson was delighted with the result, which was ''no small achievement''.