The painting, one of Warhol's Dollar Sign portraits that was created in 1981, is worth at least US$100,000 (S$142,000), according to the lawsuit, which was filed on Tuesday in New York State Court. Another Warhol Dollar Sign sold for US$4.5 million at a Christie's auction in 2006.

The lawsuit, filed by the Martin Lawrence Gallery, asks that Mr Jason Beltrez, who delivered the painting to Christie's, return it, but does not seek money damages.

Christie's, which has agreed to hold the artwork until the correct owner is identified, is also named in the lawsuit, but 'solely as a stakeholder'. The painting was one of two Warhol Dollar Sign paintings stolen from the gallery in 1998. The gallery filed a police report at the time and contacted the Art Loss Register, which maintains a database of lost and stolen art worldwide.

In 2007, after Mr Beltrez emerged with the painting, Christie's approached the Register, which confirmed that it was the same painting stolen from the SoHo gallery, said Mr Chris Marinello, the register's general counsel.

'It really was a textbook case for us,' said Mr Marinello.

'You had a seller who may not have been your typical Andy Warhol consigner and you have a major auction house that's doing the right thing.'

The gallery has requested that Mr Beltrez return the painting, but Mr Beltrez has refused, according to the lawsuit. His lawyer did not immediately return calls for comment.

'We appreciate the continued efforts of the professional auction houses and the Art Loss Register and similar agencies in the efforts to recover lost or stolen art for the benefit of the public and the art industry,' Mr Eric Dannemann, the gallery's president, said in a statement through his lawyer.

Mr Keith Carlisle, a lawyer for the auction house, said in a statement that Christie's could not comment on pending litigation. 'We are simply storing the work of art until the lawsuit is resolved,' Mr Carlisle said. -- REUTERS