"Please wait for five minutes."
The English sentence could have been written "please wait five minutes" and still have been grammatically correct. I think the word "for" in this sentence is optional and meaningless. The phrase "five minutes" can already be used adverbially.
So there should be no need to add a Japanese particle to perform the equivalent of the absolutely nothing the word "for" is doing in this sentence. :P
I was expecting 五分間まってください, but the 間 wasn't available. Would it have been kosher?