A spa pool at the Auckland Council-owned Onehunga War Memorial Pool and Leisure Centre has been closed after legionella bacteria was found.
The bacteria was detected in two water samples, and the pool was closed last week.
The pool has been treated, including a deep clean and additional chlorination, but will remain shut for two or three weeks.
Legionellosis is a respiratory infection caused by legionella bacteria. When it causes pneumonia, it is known as Legionnaires' disease - which can be serious.
The early symptoms of legionellosis include muscle aches, headache, tiredness, loss of appetite and coughing followed by high fever, chills and occasionally diarrhoea.