Warm, wet weather conditions have led to a jump in flea numbers with an outbreak in Auckland hitting schools, homes, offices and even a gym.
Some parents have said their children are coming home from school covered in bites.
Exterminator Mark McDonald said he has seen an increase in infestations as summer approaches.
"We've got quite a wet spring and had quite a mild winter so you're getting quite a good population because we've got plenty of water and we've got great habitats.
"So now they're looking for food."
While they are most common in homes with pets, Mr McDonald said he was also seeing places with no animals being infested.
The most common irritation from fleas are the bites - but in rare cases they have the potential to be a public health risk due to their ability to transmit infectious diseases.