The Manchester United striker was withdrawn at half-time of the Netherlands' final warm-up game against Wales in Amsterdam on Wednesday with a groin issue, but insisted it was only as a precautionary measure after he felt some discomfort.
Van Persie added that he had also fully recovered from the knee injury which kept him out action for two months towards the end of the Premier League season.
"Against Wales, I stayed behind in the changing room for the second half just to be careful because the match against Spain is much more important," he said of the opening game for the Dutch at the World Cup in Salvador on Friday - a repeat of the 2010 final.
"My groin was progressively a little irritated. If it had been a sudden pain I would been concerned but you can't really even call it an injury."
As far as his knee was concerned, Van Persie told De Telegraaf that he continued to work daily on strengthening the muscles.
"I've had no twinges from the knee since the injury healed and that's several weeks now. Obviously, I've had to make an effort to get my fitness back and that I've build up perfectly in training over the last weeks."
The Netherlands will also face Chile and Australia in World Cup Group B.
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