West Coast health authorities say 100 children have had whooping cough on the coast in the past five months.
The district health board says there have been 14 more suspected cases in the week to Friday.
The outbreak is still centred on Westland with most cases occurring in older children, but there have now been isolated cases in Buller and Grey districts.
The health board says there's a free booster vaccine for health workers, early childhood education staff and those living with a baby under six months.
But it says the best protection is for children to be vaccinated on time, at six weeks, three months, five months, four years and 11 years.
The DHB is asking anyone with a child who has a consistent cough to keep them at home and stay home themselves.
