The installation Sunflower Seeds by Chinese artist Ai Weiwei in London runs until May 2, when it will be shipped back to the artist's Beijing studio. ((Lennart Preiss/Associated Press))

Chinese conceptual artist Ai Weiwei has filled a hallway in London's Tate Modern museum with 136 tonnes of what looks like sunflower seeds.

Chief curator Sheena Wagstaff described the new work, on view for the media Monday, as a "beautifully simple idea that belies an extraordinary rich layer of meanings and references."

The acclaimed 53-year-old artist was invited to do something dramatic in Turbine Hall, which has been the locale for some audacious projects in the past, including  Doris Salcedo's Shibboleth, a deep fissure running through the concrete floor and Olafur Eliasson's The Weather Project, which filled the space with mist and mirrors.

Though the grey objects look like seeds, they are, in fact, handmade from porcelain and individually handpainted with a few brush strokes. The seeds cover 1,000 square metres of the hall.

Ai Weiwei says it took about 1,600 artisans to create the 100 million pieces, all crafted in the southern Chinese city of Jingdezhen.

"Historically, the town's only activity has been making porcelainware for over 1,000 years," the artist told the Guardian newspaper. "The super-high-quality skill for generations has been making imperial porcelainware. In modern days, however, it has become very commercialized."

Each seed was moulded, fired and painted. He adds that the workers had been paid slightly more than a living wage to work on the project

Sunflower seeds have symbolic significance in Chinese culture and history. During the cultural revolution, Mao Zedong was often compared to the sun and the people to sunflowers, gazing admiringly at his face.

The museum says it's encouraging people "not to depart with a souvenir."

Called Sunflower Seeds, the installation, which opens to the public Tuesday, ends on May 2.  The seeds will then be shipped back to Ai's studio in Beijing.