Japan have until the end of September to provide updated details to World Rugby regarding the 2019 Rugby World Cup after it was revealed the new National Stadium will not be ready in time.

World Rugby released a statement on Wednesday outlining a "revised roadmap for the Japan Rugby 2019 organising committee [JR 2019]", which focuses on an amended venue list and tournament budget.

Last month, Japan's Prime Minister Shinzo Abe announced the country's new National Stadium's design will be revamped to reduce costs, meaning it will not be completed in time for the 2019 World Cup.

World Rugby reiterated its disappointment at the Japanese Government's decision but insisted it was confident "the first Rugby World Cup in Asia will be a resounding success".

By the end of September, JR 2019 must provide:

• A revised detailed host venue proposal that delivers exceptional team and fan experience, maximising opportunities for fans to be a part of rugby's showcase event
• A revised tournament budget with appropriate financial security

The new National Stadium in Tokyo was set to host the opening match of the 2019 World Cup, plus the final and "other key clashes".