Authorities found out about about the infection on Sunday and issued the health alert this morning after discovering the person had visited a Canberra restaurant and chemist during the contagious period.

Acting ACT Chief Health Officer Dr Paul Dugdale said the person - who is now recovering well - was infected on a recent trip to Asia and developed symptoms upon arriving back in Australia.

He urged anyone who may have visited the Asian Noodle House in Dickson between 7 and 8.30pm on the night of October 17, as well as the Chemist on Northbourne Avenue in Civic between 7.45 and 8.45pm the same evening, to keep an eye out for symptoms until November 4.

Staff at both venues, as well as family and friends to come in contact with the patient, have been notified and checked by health authorities.

"Measles is very, very contagious, one of the most contagious diseases we have," Dr Dugdale said.

"We obviously don't [name the businesses] lightly and it's not fault of the restaurant but it just happened people may have been exposed there."

Authorities have also contacted people who may have been in contact with the infected person in other public places where they can be traced, including the emergency department.

Measles is not naturally found in Australia but spread from people returning from overseas.

Unvaccinated people and babies under 12 months old are most vulnerable, while people aged between 25 and 51 are also at risk of infection.

Anyone in that category should check with their GP if they need a second dose of the vaccine before going overseas.

"Australians travel a lot and are at risk of exposure in countries where the vaccination program is not so strong," Dr Dugdale said.

"We respect personal choice but it is very important for people [to be immunised] to grant protection for themselves, for their family and friends and colleagues and others they come in contact with."

This is the first case of measles to be reported in the ACT this year. No further cases of the highly contagious disease have been reported since.

Symptoms usually develop 7-18 days after being exposed to a person with measles and may include a fever, tiredness, a runny nose, sore eyes and a cough, followed by a rash which appears 2-7 days later.

People are infectious from the 5 days before they develop a rash until 4 days later. The disease is spread when a person coughs or sneezes, or through direct contact with run-off from the nose and mouth.

Measles cases in Sydney and Melbourne sparked health fears earlier this month, when at least 11 people were diagnosed with the infection in Victoria over a fortnight.

On Thursday, the World Health Organisation announced annual deaths from measles dropped below 100,000 internationally last year for the first time, though the world was still far from achieving elimination goals.

More information about measles can be found at ACT Health.