I've seen this before in a USA
Deluxe Strat. Right from the factory!! Oops little slip in QC.. Hehe
We noticed it when we tapped on the neck, you could clearly hear something moving around. And of course there aren't many things in a guitar neck. We tryed to tighten the rod and it didnt do anything. The neck was defective and sent back. With the whole guitar of course.
Bring it to a tech and get another opinion. Trying to tighten it is worth trying of course, but be prepared. Hopefully it's still under warranty, if you bought it new, and you don't get stuck with a bum neck. Even then depending what the guitar is worth you could have a new rod installed. They'd have to remove the freboard and what not.
Good Luck!