NSW Health is advising people to be alert for the signs and symptoms of measles across Sydney.

A person infected with measles was recently confirmed in Sydney.

This person had no contact with other measles cases and did not attend any known infection sites in Sydney.

Because the source of infection is unknown, measles may be currently circulating in the community and others may have been unknowingly exposed to measles.

In addition, NSW Health last week advised that measles patients were attending a number of facilities across Sydney, as reported on the NSW Health website.

Dr Mitchell Smith, director of public health for the South West Sydney Local Health District, said measles is a vaccine-preventable disease and is spread through the air when an infectious person coughs or sneezes.

"Symptoms to look for include fever, sore eyes, runny nose and cough, followed by a red patchy rash that usually appears three to four days later and spreads from the head and face to other parts of the body," Dr Smith said.

"After exposure, it can take up to 18 days for symptoms to appear. It is important that people remain vigilant and if they develop symptoms, they should call their GP or emergency department ahead of time and avoid spending time in the waiting room with other patients."

"We want to remind people in the community to make sure their vaccinations are up to date. This should serve as a reminder to everyone to make sure they are protected from measles, which is highly contagious."

"People born after 1965 should ensure they have received two doses of measles vaccine. This is especially important before traveling abroad as there are currently measles outbreaks in several parts of the world."

"The measles, mumps and rubella (MMR) vaccine is safe and effective and is given free of charge to children aged 12 and 18 months. In New South Wales, it is also free for anyone born in 1965 or later who has not yet had their second dose.

"Children under 12 months of age can receive an additional dose of MMR as early as 6 months of age if they are traveling abroad. Parents should consult their GP."

"The booster shot is safe, so anyone who is unsure whether they have received both doses should receive the vaccine.

This is especially important before traveling. The MMR vaccine is available from general practitioners (for all age groups) and pharmacies (for people aged 5 and over). Click here to learn more about measles Measles fact sheet.

If you or a loved one are experiencing symptoms of measles or have any questions about measles, please call your GP or healthdirect on 1800 022 222.