Three Melbourne students have been confirmed to have measles and two other cases are suspected.

Three students at a Melbourne primary school have measles.

Another two pupils at Essendon North Primary School may also have the infectious disease.

The students visited a number of local places while they were infectious but not displaying symptoms, prompting a health alert for people in the Essendon area from Victoria's chief health officer Dr Rosemary Lester.

"All five pupils have not been immunised, further strengthening the importance of parents and guardians ensuring their children are vaccinated against highly infectious diseases such as measles," Dr Lester said on Wednesday.

Students, staff, volunteers and visitors who aren't immunised aren't being allowed into the school for their protection.

Measles usually begins with common cold symptoms and the characteristic rash usually starts in three to seven days after the first symptoms.

Copyright AAP 2014