The Work is a 2017 American documentary film following three civilians on a four-day group therapy retreat with Folsom State Prison inmates. The film is the directorial debut of Jairus McLeary and was co-directed by Gethin Aldous.
It will be part of The Modern Art & Design Auction at Anderson & Garland Auctioneers in Newcastle later this month.
The model village owners said The Work had been " a life-saver".
Merrivale's owners, Frank and Frances Newsome, said they did not notice it until Two Days later when it was pointed out to them by a visitor.
Mr Newsome has previously revealed how when placing his work at The Venue .
Merrivale subsequently put it in a protective box and displayed it only at certain times of The Day , employing additional security to deter robbers, who may be attracted to artworks by Banksy, whose creations can sell for millions.
The Owners said they decided to auction the piece due to the ongoing security risk if it was left in situ.
" The Banksy has been a life-saver for us as we've had to close so much due to the pandemic, " Mrs Newsome said.
A valuer for Anderson and Garland said unique pieces by Banksy " can be difficult to value" but it was " looking for around The High hundreds of thousands up to a seven-figure sum".
The Village plans to replace the Banksy with a replica.
, which runs The Museum , said the artwork had helped it have its " ".