Vladimir Logvinenko said he is under no legal obligation to return the painting "Tarquinius and Lucretia," which was last publicly displayed in 1942 in the Sanssouci palace in Potsdam, Germany, the daily Izvestia reported.
"I am absolutely convinced that I am the rightful owner of this painting," he told the paper.
Logvinenko, who said he is in the real estate business, said the painting changed hands several times before he bought it in a legal transaction for an undisclosed price.
Germany's culture minister Christina Weiss said over the weekend that that a dealer had tried to sell the masterpiece, triggering an international effort to recover the work.
Logvinenko said he surrendered the painting to Russian authorities when he realized Germany was petitioning for its return, but the businessman expects to get the art back.
The head of the Russian Culture Ministry's department for the preservation of valuables said Monday that Logvinenko was the legal owner of the painting.
"Today's owner has the right to do with the painting what he sees as reasonable," Anatoly Vilkov said on Channel One television.
Dated from 1610-1611 the painting is one of thousands of works of "trophy art" - artwork stolen by occupying armies in Germany and Russia during the Second World War.
Logvinenko said his lawyer offered to return the painting to the gallery in exchange for a payment equal to a quarter of the work's estimated value of $92 million. But now he hopes the work will remain in Russia as his property.
"It will probably become an exhibit in a leading Russian museum," he said. "But it will still be mine."
Many Russians see the looted art as compensation for the 20 million deaths, untold injuries and immense destruction the Soviet Union suffered after it was invaded by the Nazis. But in recent years, Russia and Germany have accelerated exchanges of looted art amid closer relations.
German Chancellor Gerhard Schroeder and Russian President Vladimir Putin are expected to discuss the return of looted art when they meet in October.