Renoir's La Parisienne was donated to the national museum
Renoir's iconic impressionist work La Parisienne, which had not left Cardiff's National Museum of Wales for over 20 years, is the star of the show.
The Art Treasures of Wales exhibition at Christie's in London is to raise awareness and funds for the museum.
The four-day event also marks the start of a year of celebrations for the centenary of the art collection.
More than 30 paintings, sculpture, works on paper and applied arts will be on show from Sunday to Wednesday at the London auction house.
La Parisienne, a legacy from the art collecting sisters Gwendoline and Margaret Davies, and one of the highlights of the first impressionist exhibition of 1874 is the star of the show, according to the museum.
Also on view are other well-known works like Cezanne's Midday, L'Estaque, of 1879 and Monet's San Giorgio Maggiore by Twilight of 1908.
The museum is using the exhibition as a platform to raise funds for the redevelopment of its displays at Cathays Park in Cardiff, where it is placing art on the ground floor.
It has received grant aid from the Welsh Assembly Government, but still needs a further £1.7m for the work which will group the collections within one continuous series of galleries by 2009.
But it also said it wanted to raise awareness of the fine art on offer for visitors to Wales.
Museum director general Michael Houlihan said: "We are holding this exhibition to give people a glimpse of our treasures in the hope that they will support us in our efforts to create a gallery worthy of the collection and encourage people to visit us at home in Cardiff to see these works of art in all their glory."
Paintings by Welsh artists and in particular the rich tradition of landscape artists led by Richard Wilson and his famous view of Dolbadarn Castle are also on show at Christie's.
More recent artists - among them Gwen John, Lucien Freud and David Hockney - are also included, along with a recent purchase, Kamikaze by Peter Blake.
Sculpture and examples of the museum's little-known collection of fine miniatures have also been packaged for the trip to London.
Charles Cator, Christie's co-chairman, said: "The exhibition in January will provide a wonderful opportunity to view some of the outstanding works of art from the museum and we look forward to welcoming visitors from far and wide to this superb exhibition."
A series of informal gallery talks by the museum's curators will be held on each day of the Christie's exhibition.