The health district has recorded six cases of the invasive infection this year, with a baby less than a year old diagnosed "recently" in the greater Newcastle area.

Hunter New England Health said the child was stable and recovering at home while close contacts were being treated with clearance antibiotics.

"Meningococcal disease can occur at any time of year, but we typically see a peak in cases in spring following the winter flu season," public health physician Dr Tony Merritt said.

"Most cases occur in infants, young children, teenagers and young adults, although people of any age can be affected."

The disease is spread by secretions from the nose and throat but requires close and prolonged contact for it to spread.

It typically begins with a fever, headache, nausea and drowsiness. Neck stiffness, dislike of bright lights and a rash of reddish-purple spots or bruises can develop rapidly.

Infants may be irritable, not feed properly or develop an abnormal cry.

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