The French publishers of a book of "lost" Vincent Van Gogh sketches on Monday threatened legal action against a Dutch museum that has questioned the authenticity of the works.

The threat follows the publication in six countries last month of "Vincent Van Gogh, the fog of Arles: the rediscovered sketchbook" in which sketches apparently from the artist's legendary stay in the southern French city are reproduced.

The Vincent Van Gogh Museum in Amsterdam, however, has dismissed the sketches as fakes triggering a war of words with publishing house Le Seuil.

Le Seuil "intends to obtain compensation for the damage they have suffered as a result of an insidious and unfounded campaign" on the part of the Van Gogh Museum, the publisher said in a statement, without elaborating on the exact legal action they intended to take.

The owner of the sketches, who is said to have had them in her possession for 60 years, is also threatening legal action.

In a statement, the art expert Franck Baille, who was involved in the discovery, added that the owner, who has not been publicly identified, "reserved the right to undertake any appropriate action to repair the damage caused by these claims that describe her as a forgerer".