An outing of luxury sportscar enthusiasts in Japan ended in an expensive freeway pileup - smashing a stunning eight Ferraris, a Lamborghini and two Mercedes likely worth more than $4 million together.

Police say they believe the accident Sunday was due to wet road conditions. This may have caused the first car, a Ferrari driven by a 60-year-old male, to slip on the two-lane highway and smash into a guard rail. Cars behind then added to the pile-up as they tried to screech on the brakes.

Police declined to comment on the total amount of damage, but said some of the vehicles were beyond repair.

NTV quoted the driver of one of the tow trucks brought in to clear the scene as saying it was the most expensive crash site he had ever seen.

No one was seriously injured, but police in Yamaguchi prefecture said 10 people were treated for bruises and cuts. Police say 14 cars were involved altogether.

The luxury cars were all in one place because they were being driven by a group of automobile enthusiasts on their way to nearby Hiroshima.