The surgeon, who has not been named, was tested as part of an investigation into how a woman he operated on at Stafford District General hospital last year had contracted the virus.
The hospital authorities said that the surgeon, whose specialist field is obstetrics and gynaecology, was now on leave pending the outcome of further tests.
Mr Harsh Duggal, consultant in communicable disease control in Mid-Staffordshire, said: 'We are contacting former patients as a precautionary measure. The risk of infection is minimal. We are not yet certain that the doctor infected this patient.'
Hepatitis B is a viral infection found in blood and other bodily fluids. It is mainly transmitted in Britain through sexual activity and the sharing of needles by intravenous drug abusers. Most people who contract the disease make a full recovery but chronic cases can lead to liver cirrhosis or cancer.
Doctors are offered inoculation against the virus but are not forced to take it. Mr Duggal said the infected doctor had chosen not to be inoculated.
The hospital mounted an investigation after a 26-year-old woman was diagnosed positive for hepatitis B on 19 January. The medical team which had performed a cesarian section on her during the birth of a baby in September was tested. The baby has not been infected. On 22 January one of the surgeons involved was found to have the virus and asked not to operate any further.
Mr Duggal said: 'The person concerned did not know he had the virus. He's now on leave and is receiving career counselling. His future has not been decided.'
He said that the patient was being supervised by her GP and is receiving counselling and advice from a senior hospital consultant.
The results of further tests which may throw further light on to how her infection occurred are expected in three weeks.
Meanwhile, GPs of the 1,000 women who may be at risk and were operated on by the doctor over the past two years have been asked by the hospital to offer counselling and, where necessary, take blood samples for analysis.
The hospital has also set up a helpline for anyone concerned that they may be at risk from the virus on 0785 230111.