Tonga has declared a Zika epidemic after confirming two people have contracted the mosquito-borne virus, with 265 suspected cases.
Health Minister Saia Piukala said three New Zealand-based Tongans who travelled to the islands for a holiday had returned home and also tested positive.
Dr Piukala said the 265 suspected cases were from those who had sought treatment for acute fever, skin rashes and flu-like symptoms.
He said 35 specimens had been sent overseas for further analysis.
The government had launched an awareness campaign and was trying to destroy potential mosquito breeding areas.
Dr Piukala said schools had been closing for one day at a time throughout the kingdom.
"The age group commonly affected here is age one to 15 years old, so that's the primary school and high school age group.
"The reason for the Public Health Department, (closing schools for one day), the school do the clean up and our staff will go and do the mosquito spraying to protect students from being bitten by mosquitoes."