Van Persie, United's top scorer last season with 30 goals, has spent a large portion of the current campaign out injured amid speculation he is unhappy with Moyes' training methods.
It was also reported by RedIssue fanzine last month a number of United players are unhappy with the lack of final-third finishing drills in training, and Van Gaal acknowleged Van Persie is happier in the Dutch set-up.
"I think he should be great in the tournament [World Cup] because he loves to play in the Dutch squad," Van Gaal said.
"The football from Man United now is, for him, maybe difficult but then he wishes to show his technique. Technique [levels] in the Dutch team [are] higher."
Van Gaal will end his second stint as Holland coach after the Brazil finals and is still keen on managing in the Premier League.
The 62-year-old has won titles as manager of European giants Ajax, Barcelona and Bayern Munich during a distinguished managerial career, which included the Amsterdam club's seminal 1995 Champions League triumph.
Van Gaal, in Brazil for a FIFA workshop for World Cup managers, told the Daily Mail Spurs had contacted him after André Villas-Boas was sacked in December.
"I am mostly interested in England because I have been a coach in Spain, Germany, in the Netherlands so I think England is the next step in my career," he added.
"It could be another club [other than Spurs], it depends on the vacancies because Spurs were already [in touch] with me.
"I prefer to be focused on this World Cup and now there' s another coach [Sherwood] so as coach, you cannot say 'I go to that club or that club', it depends on circumstances."