A measles alert has been issued for a major airport, university, several flights and shops in Victoria.

Five people have been diagnosed with the highly infectious disease, including two people travelling on planes.

Melbourne Airport's international terminal is an exposure site on the morning of February 19, while the domestic terminal is an exposure site in both the morning and evening of February 27.

Flights under the alert are Singapore Airlines flight SQ217 from Singapore to Melbourne on February 14, Virgin Australia flight VA815 from Melbourne to Sydney on February 27, and Qantas flight QF483 from Sydney to Melbourne on February 27.

The alert also applies to the Craigieburn Post Office, several sites at Monash University's Clayton campus, Clayton Woolworths and the Better Choice Werribee petrol station from February 28 to March 1.

Victoria's health department has urged anyone who may have come into contact with a case to look out for symptoms up to 18 days after they were exposed.

Symptoms include a rash that starts on the face then spreads, feeling unwell, a fever, cough and sore throat.

Further details about exact exposure times can be found on the Victorian Department of Health website.