Health agencies on the West Coast say an outbreak of whooping cough, or pertussis, shows no sign of waning, with a further 18 cases in the past week.
The outbreak is centred on Hokitika and 152 cases have been reported so far.
Medical officer of health Cheryl Brunton says parents should keep children home from school or pre-school and stay home from work themselves, if they develop a persistent cough.
Two children are in hospital with complications.
Nelson/Marlborough has also had an upsurge of cases in the past two months.
Medical officer of health Jill Sherwood says there were 14 cases whooping cough in August and 14 more so far this month. The average is usually six per month.
Wellington cases reported
A medical officer of health, Stephen Palmer, says a toddler is the latest to be confirmed with whooping cough in the Wellington region.
The 18-month-old was confirmed to have the disease on Friday night after being admitted to hospital.
Dr Palmer says there have been six cases of the disease in the Wellington region.