Group Chief Executive of the WRU, Roger Lewis, said: "I am confident that we can present compelling reasons why Rugby World Cup games should be held in Wales in 2015. The Millennium Stadium is recognised throughout the rugby world as one of the finest stadiums around today.
"Secondly, Cardiff is only two hours by train from London and 25 minutes across the border from England. And most importantly, the financial model we have created with the RFU guarantees the success of the 2015 World Cup.
"I want to congratulate the RFU on the successful progress of their excellent bid and I am delighted they want to seek approval for games to be played at the Millennium Stadium.
"I have spoken to the chairman of the RFU Martyn Thomas, and passed on my best wishes for a tournament that will undoubtedly be a fantastic boost for our game.
"I am confident the IRB Council will fully understand the positive localised arguments in favour of games taking place at the Millennium Stadium and I will personally work as hard as possible to press that case so that Welsh rugby fans can enjoy the 2015 RWC to the full.
"As well as its location the stadium boasts a retractable roof which ensures that the games will always take place in decent weather conditions.
"This week we have seen how important a retractable roof can be at Wimbledon so everyone understands the value of such a system in a major tournament which attracts worldwide TV attention.
"Today I am also delighted for everyone in Japan who has worked so hard to secure the recommendation of their nation as host for the 2019 tournament. Phil Davies and our U20 squad have been full of praise for the great welcome they received at the recent Junior World Championships held there."
Under the RFU bid it is proposed that six pool stage matches would take place at the Millennium Stadium along with two quarter final matches.