Holland coach Marco van Basten has put midfielders Nigel de Jong and Stijn Schaars on World Cup stand-by as worries about the severity of injuries to Wesley Sneijder, Phillip Cocu, Giovanni van Bronckhorst and Rafael van der Vaart intensify.

The Dutch are due to open their World Cup campaign with a game against Serbia & Montenegro on Sunday but the team's injury problems are threatening to derail their ambitions.

"We're not certain if any of them needs to be replaced but it's better the substitute is available immediately," said a Dutch FA representative. Injured players can be replaced up until 24 hours before the first game.

Hamburg player de Jong was left out of the original squad because of a knee operation, but has now made a full recovery, while Schaars is the captain of the country's Under-21 side.

Sneijder, Cocu and van Bronckhorst all picked up knocks in Sunday's bad-tempered 1-1 draw with Australia, while van der Vaart missed the game with an injured ankle.