Fears of a public health threat are being hosed down by authorities in Victoria after the revelation a doctor has been suspended from practice because 12 of his female patients have contracted Hepatitis C.

The anaesthetist has the disease and police and the Medical Practitioners Board are investigating how it was transmitted to the women.

The Department of Human Services says DNA tests have linked the strain of the virus found in the women to the strain the doctor has.

The doctor has not been named, but he was working at an abortion clinic in Melbourne between June 2008 and December 2009.

Critics say the public should have been notified about the possibility of infection far sooner.

Hepatitis C takes a long time to surface. It can cause fatal liver problems and is very hard to treat.

People with the infection can pass it on if their blood gets under the skin or into the bloodstream of another person, possibly through the use of a shared syringe.

In this instance the anaesthetist passed his Hepatitis C onto 12 women, many of whom were pregnant when they were infected with the disease between June 2008 and December last year.

At the time the anaesthetist was working at the Croydon Day Surgery in outer east Melbourne.

Health authorities do not know how it happened. They do not believe anyone else has been infected but they cannot guarantee it.

Victoria's chief health officer, Dr John Carnie, says other people who visited the surgery are being tested.

"I mean I am pretty confident that if there were any other notified cases we would have picked them up. But for completeness sake we are going to call these other people back and get them tested as well," he said.

Accident or deliberate?

Dr Carnie says he cannot explain how 12 people could be infected by accident.

"Accidents might involve say one or two patients, but we are dealing with a cluster of 12 patients. So at this stage there is nothing in the processes and procedures at this clinic that would enable me to explain how it happened," he said.

He says investigations began in December when three people presented with Hepatitis C who had each been treated at the clinic over a six-month period.

Officers asked for all staff involved in surgical procedures to be tested.

"All of the staff at the time tested negative except for one of their medical practitioners who happened to be overseas at that time," Dr Carnie said.

"So on that person's return from overseas we arranged for that person to be tested - and this was at the beginning of February - and the results were clear, the person was Hepatitis C positive.

"We then asked the lab to conduct what are called sequencing studies. What it means is comparing the structure of a virus that you get from patients and comparing that structure with the virus that was obtained from the doctor concerned; similar to I guess doing a kind of fingerprint matching if you like.

"And the laboratory has found that there is a clear link from a structural point of view between the viruses of the three patients that we initially identified and that of the doctor."

Notification criticism

There are concerns authorities took too long to notify the public about the possibility of infection.

National president of the Maternity Coalition, Lisa Metcalfe, says it has taken a long time for authorities to act and women are vulnerable.

"Where medical practitioners have been acting inappropriately and it has taken the Health Department some time - I mean 12 cases is a lot of women to be exposed to this kind of alleged abuse," she said.

"It has taken a long time for them to actually act on it and to have effect, take effect and to do something about reining these medical practitioners in."

In 2008 in the United States a district health authority in Nevada issued a public warning and called on people who had used a Las Vegas clinic over a four-year period to be tested for Hepatitis C and HIV.

The warning came after an investigation found the clinic had been responsible for unsafe anaesthesia injection practices.

The Southern Nevada Health District identified six cases of Hepatitis C at the clinic, five of which stemmed from procedures on the same day involving anaesthesia.

It said a syringe that was used to administer anaesthetics to one patient may have contaminated the vial from which the anaesthetics were drawn. Intended for single use only, the vial was subsequently reused.

The district advised 40,000 patients to contact their doctors and get tested for the disease.

Nothing like this happened in Victoria. Instead authorities went to the clinic and asked for a record of patients. Officials are gradually going through the list and contacting patients one by one.

Chief health officer Dr John Carnie says they did not want to alarm members of the public by issuing a warning in the first place back in February.

"We are in the process of starting to call people back, other people who may have had procedures at this clinic," he said.

"We didn't want them to be alarmed by a call from the department but we wanted them to be aware of the issue that we are dealing with, and that was the reason for making this public."