Art critic Benoit Landais is convinced the work belongs to Van Gogh

The work was spotted at a Paris flea market in 1991 and bought for 1,500 euros ($1,800).

It was expected to fetch more than 1 million euros ($1.2m) at auction on Saturday, but was withheld to allow further scrutiny by experts.

Amsterdam's Van Gogh Museum previously pronounced the wood-on-oil painting a fake, but several experts disagree.

The painting, titled "the Labourers", depicts farm workers under a heavy sky.

Transparency

It was expected to be the star item in an auction at the weekend in the town of Portets in south-western France.

Auctioneer Eric Le Blay said the sellers had been convinced that the work was genuine, but preferred to postpone its sale when the Van Gogh Museum offered to have another look.

"In the interests of transparency, we prefer to postpone the sale. Based on the results, we will put it up for sale again," le Blay told Reuters news agency.

Van Gogh Museum curators have twice declared the painting to be a fake.

But an Italian laboratory identified its pigments as dating from the 19th century, and said the colours were identical to other paintings by the Dutch artist.

Tests showed the "Vincent" signature at the painting's corner to be at least a century old, and the varnish to match the type used by Van Gogh.

International interest

Van Gogh expert Benoit Landais says he is convinced that "the Labourers" is an original, dating back to 1883.

He says the work was listed in an 1890 inventory, which was made after Van Gogh committed suicide, but was lost after 1894.

The auction house had put up extra seating space for 300 people and 10 new phone lines with translators to match the international interest for the painting.