Number of Legionnaires' disease cases in Sydney reaches 8

Three more cases of Legionnaires' disease have been confirmed in Sydney in a recent outbreak, bringing the total number of cases to eight.

The disease is believed to have been sparked by an infected water cooling tower in Sydney's central business district (CBD).

Vicky Sheppeard, New South Wales (NSW) state health director of communicable diseases, said the search area to find the cause of the disease had been expanded.

"This is the very end of the exposure period, from what we know may have occurred ... we are not aware that there is any ongoing risk in the central business district," Sheppeard told the Sydney Morning Herald on Friday.

"Due to the incubation period stretching from two to ten days, the routine maintenance and cleaning of the water cooling towers may have already corrected the defect that caused the outbreak," Sheppeard said.

"But of course we continue to monitor everyday emergency department attendances and admission to see if any further cases arise."

Legionnaires' disease is a type of pneumonia that causes fever, chills, a cough and shortness of breath.

The last outbreak of Legionnaires' disease occurred in Sydney in 2011. Endit