MELBOURNE, March 24 - All classes at Red Hill Consolidated School, in Red Hill on the Mornington Peninsula, were cancelled on Wednesday afternoon.

An Education Department spokesman said the school was working with the Department of Health and Human Services to investigate the cause of the outbreak, which has affected 180 of its 600 students.

"Parents who are concerned about their child's health are urged to seek medical advice," the spokesman said.

Just over 40 per cent of the school's staff are also believed to have fallen ill over the past week.