SHANGHAI - Record-breaking contemporary artist Zhang Xiaogang said a purported painting of his to be auctioned in Beijing was in fact a fake.

The portrait of a young girl was among the modern and contemporary artworks that Beijing Tranthy International Auction Co Ltd had gathered for its autumn auction.

On Tuesday, a Sina micro blogger asked Zhang to authenticate the painting. He replied on the website: "It's a bad fake at first sight. Poorly done. How dare someone put it up for auction."

Zhang, 53, has repeatedly set auction records. He is most famous for his stylized, monochromatic portraits of modern Chinese people. Earlier this year, a triptych, or three-part painting, by Zhang sold for $10 million, a world record auction price for Chinese contemporary art.

Tranthy Auction has withdrawn the piece Zhang identified as fake from the auction and apologized to him.

A source with Tranthy who refused to be named said that on June 2 the painting sold for 1.8 million yuan (then almost $278,000) at Beijing Yinqianshan International Auction House.

The source said that the buyer then submitted it to Tranthy for sale. Tranthy declined to disclose the identity of the client and said it would be cautious in future dealings with him.

However, Wang Xinghua, president of Yinqianshan, told Guangzhou's Nanfang Daily that the painting was auctioned on June 2, but the winning bidder refused to pay for it. The painting was returned to the client who submitted it.

It was unclear why the explanations from the two auction houses differed.

Wang also told the newspaper, citing China's auction law, that "the artist's opinion doesn't necessarily make the final verdict for the appraisal of an artwork. Also, the auction house gives no guarantee for the authenticity, quality or defect of the auctioned item".

He went on to challenge the painter: "Does Zhang remember clearly how many paintings he has done through his life?"

Neither Yinqianshan nor Tranthy was willing to disclose the identity of their client.

Shanghai's Oriental Morning Post said Zhang was consulted about the painting in June, when it was on auction at Yinqianshan. He said then that it was fake and never expected it would be put under the hammer again. The latest news that it was up for auction prompted him to state on the micro blog that it was fake.

Zhang is abroad and could not be reached for comment.

The painting was submitted to Tranthy Auction on Saturday and no formal evaluation has been performed.

"We haven't signed the auction contract with the client yet," said Cao Liang, a Tranthy spokesman. "It would have to go through a formal appraisal before being listed as a candidate for auction."

A manager at Tranthy told the Oriental Morning Post that the painting was accepted to its warehouse because it was auctioned once before and listed in a reputable online data bank of Zhang's paintings.

Tranthy was founded in 2003 and has specialized in dealing modern Chinese ink art and calligraphy. It ventured into contemporary art in the spring.

China's laws allow auction houses to include clauses in contracts that exempt them from legal obligation if a piece turns out to be fake.

Chen Danqing, an artist and writer, said he has discovered about two dozen paintings falsely attributed to him. Neither he nor buyers of fakes could do much about the problem.

"The art market has been hot for the past years and it's unavoidable that some players will break the rules," Cao said.

To address the problem, China needed reputable auction houses to establish themselves, he said. "Thousands of auction companies are dealing in art in China. Only a few will turn out to be in it for the long haul."

Last month, a painting attributed to modern Chinese artist Xu Beihong was identified as a fake by a group of former art students. They said The Body of Miss Jiang Biwei, which sold for 72.8 million yuan ($11.4 million) at auction last year was painted by one of them.