Children on a shopping centre playground may have been accidentally exposed to measles after the highly infectious disease was discovered in a second Sydney infant.

The seven-month-old baby recently returned from the Middle East, where there have been outbreaks of measles in several countries.

Those outbreaks and an earlier infection in a travelling infant led health authorities on Thursday to encourage all recent travellers to Asia and the Middle East to look out for symptoms of measles.

People should also check, via the Medicare app or other sources, that they are up to date with their vaccinations.

"The measles vaccine can prevent the disease after exposure if administered early enough," Sydney Local Health District's John Hall said on Wednesday.

Children are recommended to be vaccinated from 12 months of age for the highly infectious disease, which is spread through the air via coughs or sneezes.

The viral illness can lead to serious complications, including pneumonia and encephalitis.

While a child's vaccine schedule can be brought forward in some instances by a GP, the seven-month-old baby was considered too young to be inoculated.

The infant was not considered to be infectious on the flight into Sydney but may have spread the disease while at a playground in the food court of Auburn Central, opposite Aldi, between 1pm and 3.30pm last Thursday.

"It can take up to 18 days for symptoms to appear after an exposure, so it's important for people who went to Chouchou BeBe Adventure Playground to look out for symptoms until January 29," Dr Hall said.

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

The case is not believed to be related to that of a nine-month-old baby who flew into Sydney International Airport on the evening of January 10 and then visited a Lakemba cafe on the afternoon of January 12.

There is no ongoing risk of infection at any of the hotspots.

NSW Health Minister Ryan Park urged people who were at or know someone who was at a hotspot to look out for symptoms.

"If you develop symptoms, please call ahead to your GP or emergency department to ensure you do not spend time in the waiting room with other patients," he said.

"This should be a reminder for everyone to check that they are protected against measles, which is very infectious."