The North African country has been in a state of unrest since violent protests forced Ali to flee to Saudi Arabia.
British Foreign and Commonwealth Office (FCO) is advising against all but essential travel to Tunisia.
More than 1,000 British nationals have reportedly been urged to leave Tunisia. Around 3,000 have already fled on emergency flights.
The FCO told C&IT that the situation is currently in a state of flux, so it is uncertain how long the disruption is likely to last.
It confirmed that between 1,000 and 1,500 expats, independent travellers and small tour group holidaymakers are still in the country.
Both Thomas Cook and First Choice have cancelled Tunisian flights.