With World Rugby starting to publicly question Japan's ability to host the Rugby World Cup in 2019, Prime Minister Shinzo Abe has sent a letter to the sport's governing body expressing the government's continued support for the tournament.

"We received word from World Rugby that (World Rugby Chairman) Bernard Lapasset received a letter yesterday from Prime Minister Abe's office," Akira Shimazu, CEO of Japan Rugby 2019 (JR2019), said Saturday.

"It was a private letter so we are not sure of the contents but we understand the letter was honest, humble and strongly worded. We are obviously involved in the process with the Ministry of Education, Culture, Sports, Science and Technology, but Abe said he would fully back any of the changes stemming from the removal of the National Stadium."