Incoming Manchester United manager Louis van Gaal is frustrated his Netherlands side will not have the opportunity to test themselves against Real Madrid star Gareth Bale and Arsenal's Aaron Ramsey this week.
The 2010 World Cup runners up will host Chris Coleman's Wales side in their final warm up game on Wednesday before setting off for Brazil.
Van Gaal was hoping to see his side come up against the world's most expensive player in Bale but a leg injury has forced the Champions League winner out of contention, while Coleman has opted to rest Gunners star Ramsey.
"I have said to my board that they have to insist on playing with Gareth Bale and Aaron Ramsey," van Gaal was quoted as saying by BBC Sport.
"I don't know why, if it is injuries or holidays," he added when told of their omissions. "When it is a holiday I'm a little bit disappointed but I can understand it, because Bale has had a very difficult and pressured season.
"It is better that we have the best Welsh team because we need resistance and I think without these players Wales are weaker."
Having seen his sider record a narrow win over Ghana after being held by Ecuador in their previous two friendlies, van Gaal was hoping for a stern test ahead of his side's Group B opener against World Cup holders Spain on 13 June.
However, with Wales also missing Ashley Williams and Ben Davies from their backline, Netherlands could be in for a slightly more one sided encounter than their manager is hoping for.
"I don't think that nowadays these results should happen. I have seen Wales playing against Iceland and Finland and I like them," the 62-year-old added. "They want to play the ball, they are not a bad team. But with Bale it's always better, with Ramsey also."