An urgent health warning has been issued across inner-city Sydney after a traveller returned from Southeast Asia with measles and visited several locations. 

NSW Health said the person attended some venues across Potts Point, Darlinghurst and the Sydney CBD while unknowingly infectious.

They dropped by over ten venues including Potts Point Laundry and Dry Cleaning, Original Backpackers Hostel, Terry Whites Chemart Kings Cross, Coles Central Kings Cross, Maryane Hair and Beaute, St Vincent's Hospital ED and Savvy Hair Boutique and Kings Brew between June 16 and 20. 

For a full list of locations and times, visit, the NSW Health website.

Measles is highly contagious and usually spreads through breathing in the virus after an infected person has coughed or sneezed. 

South Eastern Sydney Local Health District Public Health Physician Anthea Katelaris urged anyone who may have been there during the exposure period to monitor for signs and symptoms of measles. 

'If symptoms develop and you've been at one of the locations at the time listed on the website, see your doctor or health service, including an emergency department,' she said.

'Call ahead to let them know that you may have come into contact with measles so you don't spend time in waiting rooms with other patients.'

She said symptoms include 'fever, sore eyes, runny nose and a cough, usually followed three or four days later by a red, blotchy rash that spreads from the head and face to the rest of the body'.

'Anyone with early symptoms who gets a rash a few days later should also think about measles, even if they haven't attended one of the identified locations, and seek testing,' she said. 

'It can take up to 18 days for symptoms to appear after an exposure, so it's important for people who visited these locations to look out for symptoms for this period.'

Pregnant women, those with weakened immune systems, and infants are deemed to be at a higher risk.  

Dr Katelaris reminded people to keep up to date with their vaccinations. 

'Measles vaccine can prevent the disease even after exposure, if given early enough,' she said. 

'Anyone born after 1965 needs to ensure they have had two doses of measles vaccine. 

'This is especially important before overseas travel, as measles outbreaks are occurring in several regions of the world at the moment.' 

More than 50 measles cases have been confirmed in the state since January.