People in NSW should be on alert for meningococcal symptoms after a Sydneysider died from the disease.

NSW Health on Sunday confirmed a person in their 50s died from meningococcal, while a Sydney teen and a person in their 60s from the Central Coast are recovering from the disease.

None of the cases are believed to be linked.

Meningococcal symptoms include sudden onset of fever, headache, neck stiffness, tiredness, joint pain, vomiting and a rash of red-purple spots or bruises.

Meningococcal is rare but can be fatal within hours if left untreated, NSW Health director Christine Selvey said.

"Early treatment is life-saving so it is important that symptoms are recognised early," Dr Selvey said.

"If symptoms rapidly worsen call triple-zero or go straight to your nearest emergency department, do not delay."

There have been 19 cases of meningococcal reported in NSW this year.

Children under five and 15 to 25-year-olds are at the greatest risk of contracting the disease.

There is a free meningococcal vaccine available in NSW for babies at 12 months, adolescents and people of all ages with certain medical conditions.