Christchurch Hospital has struggled to cope this week as a norovirus outbreak has combined with high winter demand for its services.
Interim general manager Ruth Barclay said the hospital had been dealing with norovirus and other stomach bugs for the past two weeks.
Twenty-five patients and one or two staff members had fallen ill, she told The Press.
Two general medicine wards were affected but were not closed.
The stomach-bug outbreak and high seasonal demand for services meant the hospital was in red gridlock where there had been no beds available for new patients for about two hours twice this week.
Ms Barclay said she expected the hospital to be clear of the norovirus by early next week.