Rugby World Cup countdown: Ireland coach Eddie O'Sullivan fears his team could face a backlash over a seemingly innocuous computer program ranking his side ahead of Australia.

Despite losing 12 of their last 13 clashes with Australia and never making it past the quarter-finals of the World Cup, which the Wallabies have won twice, the International Rugby Board (IRB) listed the Irish ahead of Australia in its inaugural world rankings.

Ireland are rated third in the world, behind England and New Zealand, with the Wallabies a close fourth.

O'Sullivan said on his team's arrival in Sydney yesterday that his side deserved their lofty ranking after winning 15 of their last 17 tests, but he was wary of the repercussions.

"It's the IRB's decision, I didn't make the rankings but we had a pretty good year," O'Sullivan said.

Australia and Ireland are both in Pool A at the World Cup and are due to meet in Melbourne on November 1st.

The Wallabies have not been at their best this year but O'Sullivan expects them to peak at the World Cup, with the rankings acting as extra motivation.

"Australia are like a wounded animal, they've got something to prove and that makes them a dangerous team. I would rather play them when they are in form," O'Sullivan said.

"They had a season that was below par for them and it was a bit of a disappointment . . . but they are a dangerous team at the moment."

Ireland, who reached the World Cup quarter-finals in 1987, 1991 and 1995 but lost a play-off to Argentina for a place in the last eight in 1999, face another tough campaign in 2003.

They play their opening match against Romania in Gosford on October 11th then take on Namibia in Sydney eight days later before things start to get a little harder.

Needing to win at least one of their last two games, they tackle the Pumas in Adelaide on October 26th before their final pool game against the Wallabies.

"It's the group of death, there's no doubt about it," O'Sullivan said.

"It's the toughest group in the tournament and the key is to get out of that group if you want to do anything."

Meanwhile, Argentina captain Agustin Pichot defended his team against claims that they would resort to foul play in next week's opening match against Australia.

Wallabies outhalf Stephen Larkham had earlier claimed that the Pumas had played "dirty" in their last meeting in Buenos Aires in November.

Larkham said he expected they would adopt similar tactics in next week's Pool A clash at Sydney's Olympic Stadium if things started going against them, but Pichot immediately dismissed the claims.

"I don't think we're dirty," Pichot said on his arrival at Sydney airport.

"We just play as physically as we can because that's our strength. Anyway it's up to the referee to decide."

Argentina have been one of the most improved sides in world rugby over the last four years but will go into the match against Australia as underdogs.

The Pumas reached the quarter-finals of the 1999 World Cup and have continued their steady progress ever since, defeating France in a two-Test series last month before going down by a solitary point against the Springboks.

They hold genuine hopes of making the quarter-finals again this time but need to win either of their pool games against Australia or Ireland as well as beating Romania and Namibia.

"Trying to qualify for the quarter-finals is going to be terrible with Australia and Ireland in our group," said Pichot, who was only handed the captaincy when regular skipper Lisandro Arbizu pulled out with a knee injury.

"Australia has a great team and playing at their home ground. It's going to be very hard for us."