Sydney, Aug 1 (IANS): Authorities said on Thursday that a major outbreak of Legionnaires' disease resulted in 60 confirmed cases in the Australian state of Victoria.

The Victorian Department of Health initially issued a public alert over "a significant increase in cases notified across metropolitan Melbourne and surrounding areas" on Monday, while the confirmed cases continued to rise in the following days, Xinhua news agency reported.

According to the newly updated warning, the health department has so far been notified of 60 confirmed and 10 suspected cases since July 26, mostly in adults aged over 40 years.

The majority of the infected patients were hospitalised, with multiple of them also admitted to intensive care for "severe community-acquired pneumonia."

Local investigators are currently probing the source of the outbreak through testing of local cooling towers and other potential sources.

The Victorian Department of Health also confirmed that the outbreak is linked to Legionella pneumophila serogroup 1, which can be detected through a urinary antigen test.

As all cases visited or reside in metropolitan Melbourne, adults aged over 40 years, particularly those with other medical conditions or immune compromise, or who smoke have been urged to stay alert and seek urgent medical care if any symptom develops.

Earlier, the health authority reported on Tuesday that 33 cases of Legionnaires' disease were confirmed in the state, after which the figure almost doubled within two days.