CHICAGO (AFP) - An American museum is casting doubt on President Donald Trump's reported claim to possess an original Renoir - revealing that it has owned the Impressionist painting for the past 84 years.

According to a former Trump biographer, the US leader claims to own the original Two Sisters (On The Terrace), an oil-on-canvas painted by the French master Pierre-Auguste Renoir in 1881.

But the Art Institute Of Chicago begs to differ.

"I'm happy to confirm that it's in our collection," museum spokesman Amanda Hicks said.

"We're proud and grateful to be able to share this exceptional painting with our 1.5 million visitors each year."

An identical work, which Mr Trump asserted to be the original, was displayed in his private jet and seen as recently as last year inside his New York home, according to biographer Tim O'Brien.

"It clearly was a knock-off," he said, adding that he told Mr Trump: "I grew up in Chicago... That's not an original."

Mr Trump continued to insist that his painting was authentic, O'Brien said.

The Chicago museum lists the Renoir as having been donated in 1933 by a local art collector, who bought it from a Paris art dealer, who in turn had purchased it from the artist himself in 1881.

This is not the first authenticity controversy to dog Mr Trump.

In June, Time magazine reportedly asked the Trump Organisation to remove from display a fake magazine cover featuring Mr Trump's face adorned with flattering headlines.