Hundreds of artworks seized by the Nazis could soon be back on the market for investors to buy.

An online catalogue of works looted by the Nazis before and during the Second World War, many of them from Jewish families, is set to be made public by the US National Archives and the Commission for Looted Art.

The site will feature documents collected between 1939 and 1961, and will display images of the artworks along with details of the original owners.

Many of the works are thought to be housed in public galleries, which could spark a number of legal battles and may see many items returned to victims' families. This could lead to a mass of artworks hitting the market, as the rightful owners seek to profit from their returned works.

The co-chair of the Commission for Looted Art in Europe, Anne Webber, said the online publication of the documents was a "major step forward in international co-operation to help resolve these long outstanding issues".

Hitler with Mussolini in 1937

The documents also contain details of Hitler's plan to create a Führermuseum in his hometown of Linz with the artworks.

In 2006, a portrait by Gustav Klimt was returned to heirs of its original owner by the Austrian Gallery in Vienna. It was subsequently sold for an estimated $135m.