A woman has died in a New England hospital with meningococcal disease.
Authorities say this is the sixth case of meningococcal disease in the Hunter New England Health region this year.
Those close to the woman have been prescribed clearance antibiotics.
There are no links between this case and any previous cases, the health district says.
Public Health Physician Dr Tony Merritt said seeking medical attention quickly may prevent the development of serious complications.
"Meningococcal disease may be very severe and the community needs to be on the alert for its symptoms. If anyone suspects meningococcal disease, they should seek medical attention immediately," Dr Merritt said.
Up to 10 per cent of patients with invasive meningococcal disease in Australia die as a result of the infection.
The first symptoms of meningococcal disease may include pain in the legs, cold hands and feet and abnormal skin colour.
Later symptoms may include high fever, headache, neck stiffness, dislike of bright lights, nausea and vomiting, a rash of reddish-purple spots or bruises and drowsiness. Babies with the infection can be irritable, not feed properly and have an abnormal cry.
He stressed that while meningococcal disease could be serious, in most cases, early detection and treatment resulted in a complete recovery.