NSW's Chief Health Officer is urging all parents to ensure their children are fully immunised before the beginning of the new school year.

Dr Greg Stewart said that children who did not have proof of immunisation might have to stay at home during an outbreak of a vaccine preventable disease.

"This is for their own protection and also to protect family and friends," Dr Stewart said in a statement.

"Childhood diseases can cause serious complications and sometimes death."

Last year in NSW there 1,907 cases of whooping cough were reported, eight cases of measles and 35 of German measles (rubella).

"While these figures have fallen over the last few years parents should remember these diseases are easily spread from person to person," Dr Stewart said.

"All children should have two doses of measles-mumps-rubella vaccine by the time they begin school.

"This is in addition to the other routine immunisations for children, to protect them against illnesses such as tetanus, whooping cough, diphtheria, polio, Hepatitis B and Haemophilus influenzae type b," he said.

Parents are advised to ensure they have the NSW Immunisation Certificate before enrolling at school as details of the child's immunisation status are collected upon enrolment.