Credit: Strabismus 1(Flickr)

A doctor who failed to properly clean surgical equipment has now led 450 patients at WA hospitals being at risk of serious viruses, including HIV and hepatitis as health authorities reported.

Last month, the WA Country Health Service said that about 250 patients could have been infected after an anaesthetist working at hospitals across the Pilbara allegedly used unclean equipment during treatment.

 The anaesthetist, who worked at a number of regional hospitals in WA's north-west between 2008 and early this month, is being investigated for breaching infection control protocols.

The potential breaches involved the use of unclean tubing used to deliver anaesthetic to patients during colonoscopies and endoscopies.

WA Country Health Services medical director Felicity Jefferies said the doctor, who treated 250 patients at hospitals in Port Hedland, Karratha and Derby, had been suspended during the investigation.

Today, Ms Jefferies told 6PR radio further investigations were needed after the initial figure was released, and now the number of patients who could be affected had jumped to more than 400.

The doctor worked predominantly in the Pilbara region, especially in Port Hedland, and also spent some time in the Kimberley and Karratha.

There are also fears the infections could spread to the metropolitan area after Dr Jefferies confirmed the doctor had worked in Perth in the past, but she said nothing has shown up to suggest that.

Dr Jefferies believed the risk to the patients in question was very low.

Previously, Dr Jefferies has said there was a very, very low risk that patients had been exposed to a number of infections through cross-blood contamination.

The diseases are blood-borne virus infections, things such as hepatitis B and C, HIV and possibly syphilis, Dr Jefferies said.

The doctor, who trained in Australia and overseas, was well experienced and not a junior doctor.