Tokyo - Rugby World Cup organisers announced Friday they had hit their target of selling 1.8 million tickets during the tournament but warned fans against touts and falling victim to scams.

Despite fears that crowds might be sparse in Japan, not a traditional rugby nation, fans have turned out in their droves, packing stadiums even for games not involving tournament heavyweights.

World Rugby chief Bill Beaumont said the tournament had "captured the hearts and minds of a nation and the global rugby family" and congratulated the Japanese organised for hitting their milestone.

There are now a "limited" number of tickets available on the official ticketing website, as sponsors and nations hand back some seats, organisers said.

However, there have been "inevitable incidents related to ticket scams, touts selling fake tickets and third-party websites selling tickets unofficially" with some fans who bought seats illegally being denied entry to games.

Such incidents are likely to increase as the pool phase hots up and the tournament enters its knock-out stage, organisers said.

"While tickets remain available, our advice to fans is to only buy through official channels to avoid being disappointed," said Beaumont.

Ticket prices vary widely, from 100 000 yen ($936) for the best seats at the final, to 2 000 yen for the cheapest entry to the pool game between USA v Tonga.