Ten cases of measles have been confirmed in the past week in western Sydney, with NSW Health warning on an outbreak and urging people to get vaccinated.
Six more Sydneysiders have contracted measles, taking the number of cases in the past week to 10, with many of those infectious while in the Auburn and Bankstown areas.
"This brings the total number of cases in NSW, with onset this year, to 19," NSW Health's director communicable diseases, Dr Vicky Sheppeard, said on Wednesday.
The most affected suburbs in Sydney are currently Auburn and Bankstown.
"The recent cases reinforce the importance of getting vaccinated," she said.
"If you develop the symptoms of measles, seek medical advice. Please call ahead to your doctor or emergency department so that arrangements can be made to keep you away from others to minimise the risk of infection," she said.
Symptoms of the airborne virus include fever, sore eyes and a cough followed by a red, blotchy rash three to four days later.
Parents of infants or others who are not fully vaccinated against measles are being urged to receive the free medication.