Stolen copies of Resident Evil 6 have been sold in Poland a month before the game's official launch, Capcom has confirmed.

"Capcom is currently undertaking a thorough investigation into reports that Resident Evil 6 is being sold ahead of its official October 2 release date," the publisher told Eurogamer.

"At this time, all we can add is that it would appear this unfortunate incident is limited to a small quantity of stolen copies of the German USK PlayStation 3 version of the game."

The total number of copies stolen is unknown, although the game has been spotted at two separate retailers.

A copy has also surfaced on eBay, with a starting bid of about AU$590 and a Buy Now of AU$1470.