MotoGP's governing body the FIM says an independent study of radiation levels at the Motegi track shows that the risk to health is "negligible" and that the Japanese Grand Prix should therefore go ahead.
Some leading riders have been adamant that they will not attend the rescheduled Motegi race in early October as they fear the effects of radiation from the nuclear power station crisis that resulted from the earthquake and tsunami in Japan in March.
But the FIM and MotoGP commercial rights holder Dorna have been adamant that there is no reason why the event, which was postponed from its original April date after the disaster, cannot take place.
The bodies commissioned the ARPA agency to carry out an independent investigation, and though a final official announcement is not expected until the end of July, the FIM has released ARPA's preliminary report.
While the study acknowledges that "air gamma intensity is higher than what it was in areas close to Motegi before the accident", it suggests that ambient radiation values at Motegi will be below those usually found in cities such as Rome and Madrid and concludes: "based on the estimate dose it can be said by no doubt that the radiation risk during the race event is negligible."
The FIM said the study should provide firm reassurance to riders as it is so specific to the conditions at Motegi.
"This study is intended to complement the information already available from various Governments and the World Health Organisation, which addresses the general situation in Japan following the earthquake and subsequent tsunami that occurred in March," said the FIM statement. "This independent investigation reports specifically on the situation in Motegi and its environs, making it much more relevant to MotoGP participants."
The governing body added that it therefore saw no reason why the race would not be rubber-stamped when the final decision is made later this week.
"Based on this information the FIM and Dorna Sports will announce later this week that, subject to there being no further serious incidents, the Grand Prix of Japan will take place on October 2 as planned," it said.
Title rivals Casey Stoner and Jorge Lorenzo are among the riders who have insisted they will boycott the Japanese race if it takes place.