Tickets for at least seven matches at next year's Rugby World Cup will be allocated by ballot after the games were oversubscribed.
The fixtures with the highest demand include three of England's pool games.
Tickets went on sale on 12 September and fans can apply until 29 September.
Half of the 50 matches currently show "limited availability" on the official website, raising the possibility that further matches may go to ballot before the deadline.
A spokesman said the tournament organisers were "very pleased with the demand", but would not disclose how many tickets had been sold.
|Most popular matches at the 2015 World Cup|
|19 September||South Africa v Japan||B||Brighton Community Stadium|
|20 September||Samoa v USA||B||Brighton Community Stadium|
|26 September||England v Wales||A||Twickenham|
|3 October||England v Australia||A||Twickenham|
|10 October||England v Russia or Uruguay||A||Manchester City Stadium|
|11 October||Italy v Romania||D||Sandy Park (Exeter)|
|These seven matches have already gone to ballot as of 18 September|
Eighteen games are still rated as having good availability - these include seven matches at Cardiff's Millennium Stadium, the only venue outside England.
Pool matches involving the other Home Nations have generated mixed demand from supporters.
Availability is limited for three of Scotland's pool games - but still good for the final and potentially crucial fixture against Samoa.
There is still good availability for two of Wales' matches and two of Ireland's pool games.
Despite being the second-largest venue with a capacity of 82,000, Twickenham plays host to three of the balloted matches.
Only one of 10 fixtures at the national rugby stadium (the pool game between France and Italy) is still showing "good availability".