Many netizens expect the government authority to end the auction.

Some netizens said that a Chinese museum should collect the historical portrait instead of it being auctioned.

The painting is expectedly worth 1 million yuan (US$120,000) to 1.2 million yuan. The sale is open to both Chinese and foreign bidders, said Mei Ligang, a spokesman for the Beijing Huachen Auction Company.

"The portrait is worth far more than its monetary value in terms of art and history," said Chen Lusheng, a researcher from the China National Museum of Fine Arts.

Zhang Zhenshi, a Chinese painter who sketched the original in the early 1950s, was chosen from more than 30 candidates to portray Mao Zedong, China's revolutionary leader.

The auction company exhibited the oil painting at a press conference a few days ago. The 91 centimeter-tall and 68.5 centimeter-wide work of art is currently owned by a Chinese-American collector.