Severe travel disruption is expected at Doha airport as neighbouring Middle East countries severed diplomatic ties with Qatar.
The major hub for international flight connections will see airlines including Qatar Airways, Etihad Airways, Emirates, Flydubai and Air Arabia being affected.
Egypt is closing its airspace to Qatari aircraft in the growing diplomatic row, with Saudi Arabia and Bahrain expected to do the same.
Several countries have cut ties with Qatar, accusing the country of supporting terrorism in the Gulf region. Qatari nationals in Bahrain, Saudi Arabia and the UAE have been given two weeks to leave.
Qatar denies backing militants and its foreign minister has called for “a dialogue of openness and honesty”. Egypt said it was closing off its airspace to Qatar from 04:00 GMT on Tuesday “until further notice”.
The Foreign and Commonwealth Office updated its travel advice to warn of “severe disruption of movement and partial or full closure of all air, naval and border crossings” into and from Qatar from Saudi Arabia, Bahrain, UAE and Egypt from the early hours of June 6.
This will lead to flight cancellations and a disruption in air and sea travel. Travellers are being advised to should contact their airline or tour operator for further information.
Qatar Airways confirmed that all flights to Saudi Arabia, UAE, Kingdom of Bahrain and Egypt had been suspended “until further notice”.
The airline said: “All customers booked on affected flights will be provided with alternative options, including the option of a full refund on any unused tickets and free rebooking to the nearest alternative Qatar Airways network destination.”