Victorian health authorities 'confident' they have located source of ...

Victorian health authorities said they are confident they have located and already disinfected the source of a deadly legionnaires' disease outbreak in Melbourne.

The detection comes after two people were confirmed to have died after contracting the disease, including a man in his 60s and a woman in her 90s.

Victoria's chief health officer said on Monday afternoon testing on a cooling tower in Laverton North in Melbourne's west had returned a positive result for Legionella bacteria. 

"I can confirm one of the towers we tested and which was subsequently disinfected earlier in our investigation has returned a positive Legionella sample," chief health officer Clare Looker said.

"This gives us increasing confidence that we have identified and already treated the source of this outbreak." 

Dr Looker said the number of confirmed cases has remained at 77 since the previous update on Sunday.

"This shows a continued reduction in the number of cases being notified each day compared to last week," she said.

"I'm confident that we are now passed the peak of the cases associated with this outbreak."

Over the weekend, health authorities narrowed down the likely source of the outbreak. 

Testing is continuing to be carried out on cooling towers on industrial buildings in the suburbs of Laverton North and Derrimut, with at least 54 in the area tested.

Authorities continue to urge anyone who has visited Melbourne since mid-July to seek medical advice if they have the symptoms of a chest infection alongside a fever, chill, cough and headaches.