The Foreign Office has advised against all non-essential travel to Tokyo and the north of Japan, while airlines last night warned customers still travelling to expect cancellations and delays.
Although Tokyo has been largely unaffected by the 8.9-magnitude quake, transport has been severely disrupted, with little or no public transport running from Narita and Haneda airports to the capital.
The Foreign Office warned travellers to expect widespread power cuts and aftershocks from the quake.
In a statement, it said: "We advise against all non-essential travel to Tokyo and the north-east of Japan whilst we assess the damage caused by the 11 March earthquake.
"There is a continued risk of tsunamis in Japan. If travelling to Japan, you should be aware that there is still widespread transport disruption, widespread power cuts and disruption to water supplies and temporary shortages of supplies to shops throughout the affected areas. Aftershocks are still occurring very frequently. There is currently no public transport to or from the airports in Tokyo."
The Virgin Atlantic London to Narita flight was scheduled to take off at 1pm today, although the airline said customers might face cancellations and said they should check its website before they travel to the airport.
British Airways flights from Tokyo Narita and Haneda airports were cancelled yesterday, but the airline said its routes to and from the two airports were scheduled to continue unaffected today.
A spokeswoman for the airline said the situation was being closely monitored and could change.
Travel group Kuoni said it had no customers in Japan when the quake hit but that it was monitoring the situation to determine whether changes would be made to future itineraries.
On Friday, 29 US flights into and out of Tokyo were cancelled. Some airlines are still operating flights but are warning passengers to expect disruption due to the situation on the ground.
Japanese earthquake coverage in full
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• Rescuers in frantic hunt for survivors as death toll soars
• Blast 'less serious' than other disasters due to better design
• Green campaigner says officials 'turned a blind eye to risks'
• William Hague and Barack Obama pledge humanitarian aid after plea for help
• 'The ground was still rocking under our feet hours later'
• Airlines warn travellers to expect delays and cancellations
• Red Cross launches appeal
• Leader: Tragedy unfolds before our eyes