Changes are expected when under-fire Ireland coach Eddie O'Sullivan unveils the team that must revive the nation's fading World Cup aspirations.

Ireland need to score a minimum of four tries and win by more than seven points against Argentina on Sunday if they are to reach the quarter-finals.

After three poor performances, O'Sullivan is under enormous pressure to wield the axe and bring in some new faces at this afternoon's team announcement.

There have been injury concerns over Brian O'Driscoll, Ronan O'Gara, Girvan Dempsey and Jerry Flannery but yesterday all four were declared fit for selection.

The quartet will figure if given the green light by doctors, while there could be call-ups for Neil Best, Malcolm O'Kelly, Denis Hickie and Geordan Murphy.

O'Sullivan revealed on Saturday he is working on a high-risk strategy that will prevent Ireland's World Cup from limping to a pitiful conclusion.

He must succeed where all others have failed because Argentina have yet to concede a try in the tournament, let alone four.

The Pumas have some dynamic three-quarters in Juan Martin Hernandez and Felipe Contepomi, but Ulster prop Simon Best insists up-front will provide the fiercest battleground.

"It's great to know we have an opportunity to get through and in terms of we know what we need to achieve that," he said. "Every time we play Argentina, they want to be as physical as possible.

"We experienced that first hand from playing them in the summer. They have been pretty confident throughout the tournament and had a great win first up against France

"But if we approach the game the way we want to then we will look to win the first and pick up the tries we need along the way. That's what we're after.

"Argentina's confidence has come from their first game — they gained a lot of momentum from that. But we see this as an opportunity for us. Argentina base their game on the forwards and they will look to dominate the scrum. We are no strangers to how they play."

Ireland have been swamped by rumours of simmering tensions and disillusionment throughout the World Cup but Best dismissed the talk.

"The rumours have come as a surprise to us because we have been tight throughout," he said. "Whoever is playing gets the backing of whoever isn't playing and vice-versa when opportunities come for guys.

"We've trained very well but unfortunately we just didn't get what we needed at the weekend. But there is no disharmony."