German magazine Focus, which first reported the case, said the Munich find could be worth 1 billion euros ($1.38 billion). The 1,400 works included paintings by Pablo Picasso, Henri Matisse and Marc Chagall, some of which authorities believe may have been looted from Jewish owners by the Nazis.
"We can't say at this stage which part of the collection is more valuable," Gurlitt's spokesman Stephan Holzinger told The Associated Press, but added that the Focus estimate was "completely exaggerated."
A search of the dilapidated property in Salzburg, Austria, last month initially turned up 60 items. But a second search revealed a further 178 paintings, drawings and objects that have since been taken to a safe location for experts to restore and catalog, said Holzinger.
Once that has happened the collector plans to publish a list so potential claimants can come forward, he said.
Unlike most of the works found in Munich, the items discovered in Austria haven't been impounded by authorities.
Still, Gurlitt has instructed his lawyer to return all works that are "justifiably suspected of being Nazi-looted art." The 81-year-old, who has a court-appointed attorney, is in ill health and has come under pressure from the German government to give up any works stolen from Jews by the Nazis.
A first such handover could take place soon, according to his representatives.
The painting "Femme assise," or "Seated Woman," by Henri Matisse will be returned to the heirs of deceased Paris-based art collector Paul Rosenberg, said Holzinger. One of those heirs is French journalist Anne Sinclair, the ex-wife of former International Monetary Fund chief Dominique Strauss-Kahn.
Gurlitt's lawyer Christoph Edel is currently in talks with six claimants over the return of other works, said Holzinger. Only about 3-4 percent of the collection—built up by his father Hildebrand Gurlitt, an art dealer who traded with the Nazis—is expected to be classified as looted art, Holzinger said.
Gurlitt's website: http://www.gurlitt.info/en/index.html