The decision was reached on Tuesday by the Ministry of Education and directors from non-government schools.
The normal school break, which was scheduled in two weeks' time, has been brought forward from April to March.
All schools across the country will be affected.
Education Minister Siaosi Sovaleni said schools would close from 1pm Friday and remain so until 14 April.
The government would review the situation and decide later whether to resume schooling or remain closed.
Tonga currently has no confirmed cases of coronavirus, however there are over 100 people in isolation.
Reports of price-gouging
The government has been receiving complaints about businesses price-gouging products in high demand due to the Covid-19 measures.
Tonga implemented a state of emergency restricting gatherings and movement, which reportedly triggered some suppliers and retailers to try to take advantage of the situation.
The Ministry of Trade and Economic Development said businesses had no valid reason to increase their prices and profit unnessarily from shortages, an increase in demand due to disasters or unforeseen circumstances such as pandemic preparations for Covid-19.
The Ministry said it would be keeping a close eye on businesses across Tonga, including the Niuas, ensuring no price gouging was occuring.
Businesses risk potentially having their licence revoked, according to the Ministry.