Harry Kewell is a doubt for Australia's World Cup second round clash with Italy on Monday after being forced to sit out training on Sunday.

The Liverpool winger was able to play in all three of the Socceroos' Group F games but is still being troubled by the groin injury he suffered during the FA Cup final.

Coach Guus Hiddink said: "Harry will not participate fully in training with the team today.

"We'll see how this situation is tomorrow. It will be the same procedure as before the Croatia game."

Captain Mark Viduka admitted Kewell is a player Australia cannot afford to be without if they are to record a shock victory.

"How much concern is there? I don't know. We just have to wait and see how the situation unfolds," said Middlesbrough striker.

"Obviously, Harry's a very important player for us and we want him to be 100 per cent fit."