NSW Health has confirmed a fifth person has been diagnosed with Legionnaires' in Sydney's inner west.

The man, in his 80s, is in a stable condition in hospital.

He reports that he first felt unwell on May 12. During his exposure period, he travelled to multiple places but did not visit the Burwood shopping centre or the Sydney CBD.

The four cases of Legionnaires' disease notified last week all reported common exposures around the Burwood shopping area. One of the four died.

Cases of Legionnaires' disease are regularly reported unrelated to outbreaks and the places visited by the most recent case are being carefully reviewed.

Environment health officers have completed taking samples of potential water sources in the Burwood LGA. So far, there have been no positive test results.

Final results will be available at the end of this week.

NSW Health, Sydney Local Health District's Public Health Unit, Burwood and Canada Bay Councils and Health Protection NSW have continued to work closely over the weekend to investigate the outbreak, including interviewing patients and inspecting potential sources to ensure any ongoing risk is minimised.

For further information refer to Legionnaires disease.