Tonga's borders have been completely shut down, with no more inbound flights allowed to enter the country.
In a statement, chief executive officer for health, Siale 'Akau'ola, said it was a measure to prevent the introduction of Covid-19.
The country is already in a state of emergency, with foreign nationals banned, and public gatherings restricted.
The restriction affects Fiji Airways, Air New Zealand, Virgin Australia, and Talofa Airways flights.
In a tweet, Tonga police said any flights that were due to arrive today have been advised to divert away from Tonga.
Update: Border close down effective today. No more inbound flights allowed to enter Tonga. #coronavirus— Tonga Police (@TongaPolice) March 22, 2020
Samoa PM urges public to follow emergency orders
Meanwhile, Samoa's prime minister has strongly urged the public to heed orders under the country's State of Emergency.
Emergency provisions, enacted in a bid to ward off the threat posed by the covid-19 pandemic, include restricting all public gatherings to no more than five people.
Tuilaepa Sailele Malielegaoi said he was concerned that people continued to congregate in large groups for weddings and church services.
Yesterday, the first day of the state of emergency, police had to close down a wedding where family members had travelled from overseas to attend.
The Samoa Observer also reports that on the same day the Methodist Church defied the orders and went ahead with a National Young Women's conference.
There were reports of other church masses in the capital Apia.
Tuilaepa said the government was trying its best to stop people from being infected, especially as Samoa did not have enough doctors to cope.
He told people they must be obey the emergency orders for their own safety.
Failing to adhere to the orders can attract fines of up to US$3,400 ($10,000 tala) or two years imprisonment.