He told New Zealand's Sunday News he has no intention of joining forces with New Zealand as the battle for hosting rights heats up.
Earlier reports had suggested the two countries would join forces to fight off the challenge from South Africa. NZRU chairman Jock Hobbs was quoted saying joining up with Japan was a "secondary option".
But Mashimo yesterday said he had no intention of aligning his union with the NZRU. "We are focusing on our bid," he said from Tokyo.
Mashimo said Japan didn't need, or want, New Zealand to help run the cup.
He also questioned the validity of reports suggesting he had requested a meeting with NZRU officials when he was in New Zealand in August to discuss a joint bid.
