Fiji will close its borders to all incoming passenger flights from Thursday until next Monday.
The health ministry said it will use that time to review border quarantine processes after a new variant of Covid-19 was discovered in the UK.
More than 40 countries have now banned arrivals from Britain after the strain, which is more transmissible but not believed to be more deadly, was confirmed.
"While our current border quarantine protocols have been effective in maintaining Fiji's Covid-contained status for 246 days ... this new strain .. could potentially pose an increased risk of inflight transmission to other passengers," the Fiji health ministry said in a statement.
The ministry said the review will assess what steps can be taken to mitigate any increased risk, and warned the closure may be extended.
Several repatriation flights are due before Thursday, and the government said any passenger on board who has come from the UK, or other passengers deemed close contacts, will be quarantined separately.