Three Atol licensed companies have failed in the last week, since the impact of coronavirus on the travel industry intensified.
Northern Ireland-based travel agency Chaka Travel is the latest failure confirmed by the Civil Aviation Authority (CAA).
The Belfast-based golf specialist, which went out of business on Friday, March 13, also traded under the names golfholidaysinsouthafrica.com and mauritiushoneymoons.com.
The CAA is sending out claims forms to affected customers.
Its website has been replaced with details of how to contact its administrators, the HNH Group.
London-based WestEast Travel, which the CAA said “predominantly sold flights”, also ceased trading on March 13.
The CAA advised its customers to contact their airlines as most bookings were not packages, so won’t be Atol protected.
Disabled travel specialist tour operator Can Be Done Ltd ceased trading on March 12.
The CAA advised travel agents holding consumer money to wait for instructions from the Air Travel Trust Fund. Agents will be individually contacted.