Following a doctor's breach of infection control protocols, it was estimated hundreds of patients in northwest of Western Australia may have been exposed to diseases such as HIV and hepatitis.

The health department of Western Australia revealed that at least 250 patients may have been exposed after they were treated by a particular anaesthetist while undergoing procedures such as colonoscopies.

The doctor has been suspended on full pay by the health department and his case has been referred to the state's Medical Board.

According to Felicity Jefferies, medical director of the country's health services, the doctor had been working in the northwest from June 1, 2008 and April 1 this year.

She said the doctor was suspended on the same day a staff member alerted the department to issues concerning the doctor's adherence to the infection control protocols.

The breach in protocol, according to Dr Jefferies was related to the doctor's use of equipment but she would not go into specific detail.

She advised people to be alert but not alarmed and stressed as the risk of infection among patients was small.

The breach was described by Dr Jefferies as minor and she said the doctor was adhering to protocols that had not been used for two decades.

All affected patients will be given blood tests and counseling is offered by the health department.