Rugby World Cup chief executive Martin Snedden says the schedule for the tournament must change in the future.
The near seven-week-long tournament has been criticised for giving the lower-ranked nations a tougher schedule than the more established nations.
"It's been difficult for some of the teams, there is no doubt about that," Snedden told BBC Sport. "Patently it's not right and needs to be worked on."
He said the problem could be solved if the tournament was longer.
The schedule we came up with was felt, by the teams, to be a lot better than what they had experienced in France and in Australia before thatMartin Snedden
Snedden, who represented the New Zealand cricket team in 25 Tests and 93 one-day internationals between 1980 and 1990, said: "The schedule is one of the most difficult things to do and we thought about it long and hard with the IRB [International Rugby Board].
"You've got a set window for the tournament. The only way you can avoid the situation that has happened is to lengthen the tournament by seven days and that's not a decision for us, that's one for the IRB and their members. If they did that they could get around some of scheduling issues."
He told the BBC's Dan Roan: "It [the scheduling for smaller nations] was looked at seriously before this tournament and the schedule we came up was felt, by the teams, to be a lot better than what they had experienced in France and in Australia before that. But undoubtedly it will be an issue looking forward."
During this World Cup, in general the smaller nations have had less recovery time with matches scheduled midweek, while the bigger nations have largely played on a weekend, giving them longer between games.
Tournament spokesman Mike Jaspers has admitted that TV audiences, wanting to see the top teams play on a weekend, were a significant factor in the scheduling of the tournament.
But this has led a number of representatives from the two-tier nations complaining of what they feel is unjust treatment.
United States captain Todd Clever, who admitted "it hasn't been ideal" that his side had to play Ireland and Russia within five days, and Georgia coach Richie Dixon, who bemoaned the fact his side had to play Scotland and England in the same week.
