Demand was so high, said Wolfgang Beltracchi, that he could have found buyers for up to 2,000 bogus pieces, had he been inclined to paint them.
Last October, he was given a six-year jail term for forging 14 paintings by six well-known artists.
One work was bought and sold by actor Steve Martin before being exposed.
Beltracchi, who begins his prison sentence this month, has not confirmed the precise number of paintings he has forged over the last four decades.
Pieces painted in the styles of Kees Van Dongen, Max Ernst, Max Pechstein and Heinrich Campendonk were among those fabricated, along with certificates of origin and labels.
Dealers, museums and art collectors were duped into believing the previously unknown masterpieces had been hidden for years by two secretive Cologne collectors.
After experts had been fooled into confirming their authenticity, it sparked a buying frenzy with galleries and auctions offering the works.
Three other people, among them Beltracchi's wife Helene, were convicted last year of forgery and corruption relating to 14 works that sold for $45m (Â£28.6m).
According toDer Spiegelmagazine, the conspirators "took advantage of an overheated art market".
A German convicted for his role in an art forgery scandal has claimed to have faked works by "about 50" different artists over the course of his career.