More than 60 additional works have been discovered in the Austrian home of Cornelius Gurlitt, among them works by masters Picasso, Renoir and Monet, said his spokesman Stephan Holzinger.
He said after a first inspection there was no indication that any of the newly-discovered works were Nazi loot, a term for artwork that the fascist regime stole from Jewish owners or bought from them cheaply under duress.
The Gurlitt case first made headlines late last year when it emerged investigators had found 1,400 artworks in his Munich flat, including long-lost works by masters also including Matisse and Chagall.
Gurlitt, 81, is the son of Nazi-era art dealer Hildebrand Gurlitt, who acquired the paintings in the 1930s and 1940s and had been tasked by the Nazis with selling stolen works and art the Hitler regime deemed "degenerate".
Germany earned criticism for dragging its feet on the case. Although the works were discovered in early 2012, the spectacular find only became known to the public late last year through a news magazine report.
On Tuesday, Gurlitt's spokesman said in a statement that "more works were located in Cornelius Gurlitt's house in Salzburg".
"They are more than 60 works, including by Monet, Renoir and Picasso," the statement said.
"At the request of Cornelius Gurlitt, the works are being examined by experts on whether they include possibly stolen art. A preliminary assessment based on an initial screening did not substantiate such a suspicion."
Berlin said last month it will boost funding for efforts to return Nazi-looted art to their rightful owners and may invite Jewish representatives to join a mediation body.