Johannesburg - Winger Arjen Robben said on Monday that he is doing everything he possibly can to be fit for the Netherland's opening World Cup match as he battles to shake off a thigh injury.

While the Dutch team has arrived in South Africa, Robben has remained back home receiving treatment.

He is hoping to join the team later this week to play in the Oranje's opening game against Denmark next Monday and then five days later against Japan, but faces a race against time.

"I am doing all I can to be fit again within a week," said Robben in a telephone interview with the TV programme Studio Voetbal.

"It is a small muscle tear on the left thigh which I have injured before.

"With conventional treatment, the muscle needs four to six weeks to heal, so now we need to use other methods."

Dutch coach Bert van Marwijk has left the door open for Robben, if he can prove his fitness.

"We want to give him every chance to rejoin the team, so I have not called up a replacement player yet," said Van Marwijk.

Robben is being treated by established Dutch physio Dick van Toorn and says he is healing well.

"I have had good experiences with Van Toorn's treatment in the past," said the 26-year-old Robben, who injured himself in Holland's 6-1 win over Hungary last Saturday.

The Dutch held their first training session here since arriving and were in good spirits, despite having to leave Robben behind in the Netherlands.

"We hope he can join us as soon as possible," said midfielder Mark van Bommel, Robben's captain at Bayern Munich.

Real Madrid's Rafael van der Vaart says the Oranje will be even stronger if Robben makes it in time.

"Arjen has been outstanding this season," said Van der Vaart.

"With him, we are even stronger."

But the Denmark camp are hoping Robben fails in his fitness bid.

"That would clearly be an advantage for us," said Danish defender Lars Jacobsen.

"He can decide games on his own and is absolute world class.

"Holland will be missing something if he really can't play."

But Danish coach Morten Olsen, said the Oranje still have world-class players like Van der Vaart and Inter Milan's Wesley Sneijder to call upon.

"Even without Robben, Holland are an outstanding team.

"And if he does not play, they will just call up another class player, so it won't necessarily make things easier for us if he pulls out."