Eilish Cleary says to date there are 100 reported cases, an increase of 53 since the outbreak was announced at the end of February.
Cleary says the outbreak has mainly hit the southern and eastern areas of the province.
Most of the cases are occurring in children in a range of ages under 14.
Whooping cough is a disease of the lining of the respiratory tract caused by a bacterium.
Health officials are advising people who have not been immunized in the last five years and are in close regular contact with children to see their doctor about getting vaccinated.