Seen for the very first time: Faltering art market given a boost

For 90 years this exquisite and rare work by the Italian artist Amedeo Modigliani has graced the home of one wealthy family. The image of two young girls was painted in the south of France in 1918 as the artist avoided the ravages of the end of the First World War. Now, for the first time, it is to go under the hammer.

Purchased from the artist by the collector Jonas Netter, who helped to established Modigliani's reputation, the work – one of only five double portraits the artist created – has been the heirloom of a single family for nearly a century.

The painting, Les Deux Filles, is one of a slew of Impressionist and modern paintings that have never been to auction but which will be sold by Christie's next month in an attempt to buck the collapse of the art market. Henri Matisse's Femme Assise sur un Balcon, 1919, for example, passed through generations of the artist's family and has never before even been loaned to an exhibition.

The art market can no longer expect to attract the fabulous sums that were being paid just six months ago by trophy collectors whose fortunes have dwindled as the global recession bites. Instead of hoping for records, Christie's and Sotheby's are offering for sale only rare paintings that would be the envy of any world-class museum in order to lure the collectors who still have money.

Also at Christie's is a 1972 Miró that was given by the artist to the current seller and has never been exhibited; a 1921 Bonnard that has never left private hands and was last exhibited for two months in 1966. Sotheby's also has works hidden from public view for decades, including a 1943 Miró last shown in 1957.

The slimmed-down auctions – the houses have selected only the best works for sale – will be watched avidly by the art market. They are the first sales since the art bubble burst in November, yet the low value of the pound and low interest rates could see foreign buyers bid more than expected.

A spokesman for Christie's said: "These sales are more targeted because it's a changed world. We have gone for works that are timeless. With some artists, you can wait for others of a similar quality to come on to the market. You can't with these works. The Modigliani is a very rare thing to come on to the market."

Helena Newman, Sotheby's vice-chairman of modern and Impressionist art, said the focus on very high-quality work was deliberate. "We have tried to bring museum-quality pieces to the sale," she said. "The sense is that what will happen now is that the old money which might have been sitting on the sidelines may well come back and bid more than they might have done last summer. From talking to our clients, the signs are that they want to buy rather than sell.

"Old buyers will be brought back; because of the pound they may be able to bid more. And with interest rates being so very low, it's a once-in-a-generation opportunity."