Taranaki Base Hospital in New Plymouth has so far avoided delays to surgery due to an outbreak of gastroenteritis.
The orthopaedic ward at Taranaki Base Hospital is locked down until at least Saturday because six patients are affected.
Only hospital personnel and essential visitors are allowed into the ward.
However, Taranaki District Health Board says no surgery has needed to be cancelled yet - although some elective surgery could be postponed.
Taranaki's Medical Officer of Health, Dr Penny Hutchinson, said on Wednesday that laboratory tests should determine the cause of the vomiting and diarrhoea within a week.
