Victoria's health authority has warned people to remain on the alert despite no new cases of measles being reported.

Melburnians are being warned to watch out for signs of measles despite no new cases being reported in the city's latest outbreak.

Victoria's health authority has warned doctors to remain alert for further infections after four cases of the highly infectious disease were confirmed in Melbourne's inner north over the past week.

No direct connection has been found between the four carriers - a man and two women in their 20s and a woman in her 40s - but all live in Brunswick and Brunswick East.

Victoria's acting chief health officer Roscoe Taylor said measles incubation period of up to 18 days meant illness acquired from contact could still pop up.

"We are concerned that more people may have been infected from coming into contact with these people in the community," Dr Taylor said.

Three of the known cases required hospitalisation but all four carriers are now home.

The source of the outbreak remains unknown.

Anyone concerned they may have the disease should call a doctor so arrangements can be made to minimise exposure to other patients, Dr Taylor said.

Young children, women of child-bearing age and at-risk groups such as Indigenous people and refugees are eligible for free vaccines.

For information on why vaccinations are important, click here. 

SYMPTOMS OF MEASLES (10-14 days after infection):
* Fever
* Sore throat
* Inflamed red eyes
* Cough
* Blotchy rash, three to seven days after first symptoms
* Pneumonia and other serious complications possible.