An international rugby chief believes that Tokyo's hosting of a Sevens World Series event this weekend will have long-term benefits for the sport's growth in Japan and throughout Asia.

International Rugby Board Chairman Bernard Lapasset said it would boost Japan's preparations ahead of becoming the first Asian nation to host the 15-a-side Rugby World Cup in 2019.

It would also attract the populous region to the sevens format ahead of its return to the Olympics in 2016, he added.

The world series returned to Tokyo for the first time since 2001 on Saturday with more than 35,000 people expected at the Prince Chichibu stadium and with about a dozen Japanese companies sponsoring the two-day event.

Tokyo has become the third stop of the series after Dubai and Hong Kong.

"It is important that the people of Japan - both those who already know and love the sport and also new audiences - are exposed to top-quality rugby as we prepare to bring the game's pinnacle tournament here in 2019," Lapasset said in an interview posted on the series' website.

"It is vital that the Japanese people are prepared for (the) Rugby World Cup and the HSBC Sevens World Series is a great way to do that," he said.

"I am confident that the city will make a good start along that road this weekend and, in future years, will build upon that success as we move closer to 2019."

Apart from raising their game, Japan have been urged to take drastic measures to raise the sport's popularity before the 15-a-side World Cup.

Japan, perennial Asian champions but minnows on the global stage, are hoping to avoid becoming the first World Cup hosts to bow out before the event's knockout stage.

At last year's tournament in New Zealand, the Brave Blossoms failed to add to their single victory at a 15s World Cup in 1991.

Lapasset believes participation in rugby is growing through major event hosting, strong development and investment programmes in Asia which currently boasts 60 per cent of the world's youth.

"These are exciting times for the ongoing development of rugby in Asia. Participation has increased by 18 per cent since RWC 2007 with more men, women and children engaging in the sport than ever before," the French rugby official said.

Lapasset said: "The IRB, working with the Asian Rugby Football Union, is committed to the development of the game in Asia through a strong programme of investment, coaching and education funded through the commercial success of (the) Rugby World Cup," he said.

"We are investing more than £150 million ($240 million) worldwide and £8.7 million in Asia between 2009 and 2012 to ensure that more men, women and children can enjoy a sport that brings people together through values of integrity, respect and solidarity."