The volcano continues to billow ash and smoke into the air
The Japanese MotoGP at Motegi has been called off because of air travel problems caused by the cloud of volcanic ash in Europe.
Organisers said the race scheduled for Sunday 25 April will take place on 3 October as championship round 14 before events in Malaysia and Australia.
"Although the situation is beyond our control, we sincerely apologise to fans," said spokesman Hiroshi Oshima.
The next round will now be at Spain's Jerez circuit on 2 May.
While most of the freight will have been flown straight on from last weekend's season-opener in Qatar, the cloud of ash has created a no-fly zone over much of northern and central Europe and made it impossible for many team personnel to reach Japan.
Formula 1 teams, a majority of them British-based, and international media have faced significant difficulties in returning from China after Sunday's grand prix in Shanghai.
Mobilityland Corporation, the Japanese operator of the Motegi venue, north of Tokyo, said it hoped MotoGP fans could attend the event later in the season.
"Due to the Icelandic volcanic eruption causing flight cancellations by aviation operators, we have decided to postpone the MotoGP scheduled for this weekend," said company president Oshima.
"We hope that fans will look forward to the added attraction."