Benteke played under Allardyce during his time in charge at Selhurst Park and there have been reports that the two clubs are in talks about a possible deal.
And the arrival of Jean-Phillippe Mateta from Mainz last week could see Benteke pushed further down the pecking order under Roy Hodgson.
Asked about the 30-year-old Belgium international, Allardyce said: "I am not sure if Christian is available, that's down to the head of recruitment and (technical director) Luke (Dowling).
"If they came to me and said Christian is available, I'm not sure that's the case at the moment, but if he is available I'd be interested."
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