A man and a baby are the latest people in NSW to be diagnosed with measles, bringing the number of cases to 11 since Christmas.

The man aged in his 50s became ill as he returned home on a flight to Sydney from the Philippines. He has been hospitalised with serious complications of the infection.

They had no record of receiving a measles vaccination, according to NSW Health.

The case prompted NSW Health to again urge people travelling to South East Asia, where measles is prevalent, to ensure they are fully vaccinated before heading overseas.