The health authorities have added the Czech Republic and Tunisia to the 'amber list' of arrivals.
Countries on the list, which also includes Bulgaria, Romania and the Spanish regions of Barcelona, Girona and Madrid, are required on arrival in Malta to produce a negative COVID-19 test taken not more than 72 hours before their flight to Malta.
Those who do not produce the result may be swabbed or put in quarantine.
The amber list was introduced last week and comes in between a 'green list' of countries from which travel is unrestricted, and a 'red list' from which ravel is banned. The extended list comes into force on Friday.
On Monday, two travellers who arrived in Malta from Barcelona tested positive for COVID-19 at the airport.
The Ryanair passengers were subject to random testing after they touched down at Malta International Airport.
It is not clear whether they had taken a test before their departure.