Another call for parents to check their children's vaccinations amidst an outbreak of measles.

Thirteen cases of measles have been confirmed in the South Island over the last month - with seven in Canterbury.

West Coast medical officer of health Cheryl Brunton says the majority of cases are in adults, but with children heading back to school and mixing with others, it's important to check they're immune.

"Measles is very highly contagious and it is difficult to control when its spreading. That's the reason why we're so keen on recommending vaccination because that really is your very best protection against measles and it's spread."