They were admitted to Harlow's Princess Alexandra Hospital at the weekend when tests confirmed the presence of the Legionella bacteria.

The men -- one from West Essex and the other from Hertfordshire -- are said to be in a stable condition.

The source of the infections has still not been traced.

We are doing everything we can to identify the cause and eliminate any risk of further infection

Dr Sally Millership

Essex Health Authority said it was trying to determine the cause of the infection.

Hospital staff and local doctors have been notified and asked to report any possible cases.

A spokeswoman for the health authority said on Tuesday that the men were admitted to the hospital over the weekend and tests confirmed the Legionella infection.

She said: "They are in a critical but stable condition but there has been some improvement.

"A team of experts in communicable disease control is investigating both cases to identify any links that could lead to the possible source of the infection.

"No link has been identified and investigations are continuing."

Dr Sally Millership, consultant in communicable disease control at Essex Strategic Health Authority, said: "Isolated cases of Legionnaires' disease do occur from time to time and it is possible that these two cases are coincidental.

"We are doing everything we can to identify the cause and eliminate any risk of further infections."