Mito is 27 miles from the race circuit and suffered earthquake damage
The Japanese MotoGP race in Motegi set for 24 April has been moved back to 2 October following the earthquake and tsunami on Friday.
Although Motegi did not suffer major devastation, roads between Tokyo and Mito - the closest city to the race circuit - have been damaged.
The MotoGP season gets under way in Losail in Qatar on 20 March.
It is the second year in succession that the Japanese round of the world championship has been rescheduled.
The race in 2010 was postponed from April to October following the volcanic ash crisis in Iceland that prevented most of the paddock from flying from Europe to the Far East.
International Motorcycling Federation spokeswoman Isabelle Larivier confirmed on Tuesday that the event had been postponed and rescheduled Sunday 2 October.
The revised date means the Japanese event will slot into the MotoGP calendar between the Aragon and Australian races.
The 8.9-magnitude earthquake on Friday caused cracks on the track and damaged spectator seats at the Twin Ring Motegi circuit, north of Tokyo.
The 18-race MotoGP season
begins on Sunday with the opening race in Qatar
and the final race on 6 November in Valencia, Spain.
Spaniard Jorge Lorenzo is the reigning MotoGP world champion.