New Zealand won the right to host the event ahead of Japan and South Africa

The earlier window was preferred by hosts New Zealand but could disappoint the northern hemisphere unions.

Next year's World Cup in France is also in September and October, affecting the fixtures of two domestic seasons.

"We have a problem for two years as a result of the World Cup," said RFU chairman Martyn Thomas recently.

"As England always said in their unsuccessful bid for next year's World Cup, the French bid will result in a disruption of two years.

"That has only just come home to roost but no-one accepted that at the time."

The placement of the Rugby World Cup is of paramount importance IRB chairman Syd Millar

The 2003 World Cup in Australia was held from 10 October until 22 November. Next year's in France starts on 7 September, with the final on 20 October.

The IRB is currently reviewing detailed proposals for a 2008-2019 international tours schedule and central to that is the creation of a permanent window for the World Cup.

Chairman Dr Syd Millar said: "The existing schedule for international matches evolved historically, but what is needed is a schedule that better reflects the modern game, takes into account all stakeholder groups and one that fits strategically with the development goals of the IRB.

"The placement of the Rugby World Cup is of paramount importance as it has a huge affect on the rugby calendar, both in the year it is played and in the four-year cycle between tournaments.

For rugby to truly become a global sport, the game needs to utilise all that Asia has to offer Japan RFU president Yoshiro Mori

"We have made forward progress on the issue and council members will review detailed proposals for an interim international match and tours schedule for 2008-2019 over the coming months, with a view to making an announcement on its implementation in May 2007."

Meanwhile, Japan has confirmed it will make a formal bid to host the 2015 Rugby World Cup, after losing out to New Zealand for the 2011 tournament.

"We have decided to go ahead and make preparations to formally bid for the 2015 Rugby World Cup," Japanese RFU president Yoshiro Mori said on Friday.

"The support we received... both in Japan and around the world, helped us greatly in making this decision.

"For rugby to truly become a global sport, the game needs to utilise all that Asia has to offer.