The two cases, a middle aged woman and a teenage male, were diagnosed with measles after contact with a man confirmed with measles on return from South America.

Both cases visited the following locations in and around Lake Macquarie and Newcastle while infectious:

. Wednesday, August 28 Wallsend Library 11:30am - 2pm, Glendale Hunter Sports Centre gymnastics class and Glendale Shopping Centre 6pm - 7:30pm. Edgeworth Town Centre, Henny Penny and Coles 7:30pm - 8pm.

. Saturday, August 31 West Wallsend Swim Centre 10:15am - 11:30am, Warners Bay Pillow Talk Midday - 12:30pm, Wallsend McDonalds Midday - 2:30pm, Kotara Bunnings 1pm - 1:30pm, Clarendon Hotel, Newcastle 2:30pm - 3pm.

. Sunday, September 1 Broadmeadow MacDonalds 8am - 8:30am, Wickham Bid Barn Tender Centre Midday - 2pm.

. Monday, September 2 Westfield Kotara, KFC and Kmart 3pm - 3:30pm.

.Tuesday, September 3 Glendale Pharmacy Chemist Works 8:30pm - 9pm.

Hunter New England Public Health Physician, Dr David Durrheim, said the locations visited by the cases did not pose an ongoing risk but he urged anyone who was in the locations at the same time to watch for symptoms.

"It can take up to 18 days for symptoms to appear following exposure to a person with measles. People in the same places at the same time as the woman or teenager should be alert for signs and symptoms of measles until September 22, 2019," Dr Durrheim said.

"Symptoms to watch out for include fever, sore eyes and a cough followed three or four days later by a red, blotchy rash that spreads from the head to the rest of the body.

"Anyone who develops symptoms of measles should phone their GP to ensure they don't wait alongside other patients before seeing their doctor.

Dr Durrheim encouraged everyone in the Lake Macquarie and Newcastle regions to ensure they had received two doses of the measles-mumps-rubella vaccine, which provides lifelong protection in 99 out of 100 people who are vaccinated.

"The measles-mumps-rubella vaccine is safe and effective protection against measles," he said.

"It's free for anyone born during or after 1966 who hasn't already had two doses. If you're unsure whether you've had two doses, it's safe to have another."

Measles is highly contagious and is spread in the air through coughing or sneezing by someone who is unwell with the disease.

While the risk of infection is low in fully-vaccinated people, health experts urge anyone who comes into contact with someone who has measles to remain alert for symptoms.

If symptoms develop they should limit their exposure to others and seek medical care. For more information on measles visit: https://www.health.nsw.gov.au/Infectious/measles/Pages/key-facts.aspx