London, England (CNN) -- Works by Picasso and Monet are set to go up for sale Wednesday in what Christie's calls the most valuable art auction ever to take place in London.
Pieces by Klimt, Van Gogh and Matisse will also be auctioned at the evening sale, Christie's said.
Giovanna Bertazzoni, the head of impressionist and modern art at Christie's, said there has been a "fierce international demand" for the "rarest and the best" in the art world.
"The strong results at our auctions over the last year, and during the last six months in particular, have further fuelled the confidence of vendors," she said. "We are witnessing a great willingness from clients to consign works of art of the highest quality".
The 63 works in the sale are expected to fetch between 163 and 231 million pounds ($242.5 and $343.7 million), Christie's said.
Among the artworks is Picasso's Blue Period "Portrait of Angel Fernandez de Soto," which is estimated to fetch between 30 and 40 million pounds ($44.7 and $59.5 million), Christie's said.
Monet's "breathtaking" water lily painting "Nympheas," from 1906, is expected to sell for the same amount, the auction house said.
