The expanded Super Rugby season, to be followed immediately by the Tri-Nations later this month, may be the biggest stumbling block in the way of a SANZAR nation winning the World Cup later this year.

England star Nick Easter says South Africa, New Zealand and Australia (the SANZAR countries that feature in the Tri-Nations) risk being "over-cooked" by the time they get to the World Cup.

He believes the northern hemisphere teams have an advantage as they'll be fresh while the southern superpowers will go into the tournament in New Zealand in September at the end of long, gruelling campaigns.

The Tri-Nations series has been reduced this year to home and away Tests against each team - four matches.

But it follows an expanded Super Rugby provincial competition which has witnessed a heavy injury toll and only ends this Saturday when the Reds play the Crusaders in the Final.

"This time the northern hemisphere teams might have a little bit of an advantage over the southern hemisphere teams in terms of the scheduling because we've had a break," Easter told the Press Association.

"We don't have any rugby matches now until the first warm-up game in August, so we have a good window to train hard and get prepared properly.

"But in the southern hemisphere their Super Rugby season is longer than usual and has gone on an extra month. Then they have the Tri-Nations.

"They might be a little over-cooked, while for us it's just like heading into a normal season.

"At our clubs we'd be doing pre-season at this time and start playing in September."

A key figure in England's surge to the 2007 World Cup final in France, No.8 Easter was not concerned that England's pool at the 2011 World Cup could leave their team insufficiently battle hardened for the knockout stages.

The Six Nations champions open the tournament against Argentina on September 10 and also face Georgia, Romania and Scotland.

In 2007, Australia and New Zealand paid a price for their romp through the group stages as they stumbled out in pressure-cooker quarter-finals, with the Wallabies losing to England.

"Absolutely you want a challenging pool. You don't want it too tough obviously because you could end up giving everything just to get out of it," said Easter.

"You definitely want some tough games or matches where not everything goes according to plan so you have to work out different situations.

"In quarter and semifinals things don't go according to plan and the opposition is as desperate as you to win it.

"If you haven't had that match practice or played under that pressure or intensity in previous matches, you can get caught on the hop.

"That's certainly what happened to New Zealand the last time around."