The first portrait of Chinese revolutionary Mao Zedong to hang on Tiananmen Square will go on auction next month, 40 years after he unleashed the Cultural Revolution, an auctioneer said Thursday.

The Mao portrait is expected to attract bids of up to 1.2 million yuan (150,000 dollars) when it goes under the hammer on June 3, Mei Ligang, spokesman for Beijing's Huachen Auction House said.

"We had an auction of historical paintings last year that did very well, so we think the market is ripe to continue to sell these kinds of oil paintings," Mei told AFP.

Painted by Zhang Zhenshi in 1950, the portrait was the first of Mao to hang on Tiananmen Square after he founded the People's Republic of China in 1949, Mei said.

The portrait, which stands just under one meter (3.3 feet) tall, has since served as the model of Mao's likeness for all the portraits that have hung on the Tiananmen Square Rostrum Building.

It is currently owned by an overseas American-Chinese collector, Mei said, without giving any more details about the owner.

The portrait of Mao on Tiananmen Square is one of the most well known symbols of China. The current portrait is six meters tall.

It was from the rostrum that Mao declared the People's Republic established.

He also addressed millions of fanatic "Red Guards," or young Chinese revolutionaries, from there during the Cultural Revolution that officially started on May 16, 1966.

The revolution was instigated by Mao to create a classless society but also to eliminate his political rivals. It resulted in political and economic chaos for the nation and ended only after Mao's death in 1976.