US first lady Michelle Obama and her daughters Malia, front, and Sasha as they visit the Mutianyu section of the Great Wall of China in Beijing.

US first lady Michelle Obama and her daughters Malia, front, and Sasha as they visit the Mutianyu section of the Great Wall of China in Beijing. Photo: AP

Chinese authorities ordered merchants to hide their stock of ‘Oba-Mao’ T-shirts this week during a visit by US First Lady Michelle Obama and her two daughters.

The popular T-shirts depict President Obama in the uniform of Mao Zedong, the founder of the Chinese Communist Party.

Vendors line the most popular and intact stretch of the Great Wall at Mutianyu, 70km north of Beijing, to sell T-shirts to tourists.

Designer and entrepreneur Liu Mingjie wears his 'Oba Mao' t-shirt in Beijing.

Designer and entrepreneur Liu Mingjie wears his 'Oba Mao' t-shirt in Beijing. Photo: AFP

According to a pool report in The Weekly Standard covering the Obama trip, ‘authorities made sure, for a day, that Mutianyu was visibly free of Oba-Mao T-shirts’.

Most vendors denied selling the T-shirts when approached by reporters, except for one more opportunistic merchant, who took a correspondent to the back of her tent and revealed an entire box of the T-shirts, and offered to sell one for 360 yuan, or an "outrageous" $64.

She put the T-shirts away after being warned about the 'ban' by other vendors.

A worker dries shirts bearing an image of US President Barack Obama's face over that of China's late Chairman Mao Zedong at a shirt printing factory located on the outskirts of Beijing.

A worker dries shirts bearing an image of US President Barack Obama's face over that of China's late Chairman Mao Zedong at a shirt printing factory located on the outskirts of Beijing. Photo: Reuters

The First Lady and her two daughters Malia and Sasha walked between Towers 14 to 15 at the Great Wall, while Obama’s mother, Marian Robinson, watched from a viewing platform nearby.

They reportedly descended the mountain at Mutianyu on toboggans before returning to Beijing.

Michelle Obama is in China to attend a roundtable discussion on education.