The 4.5-tonne sculpture, welded together from deactivated guns, landmines and ammunition, has been shown in many countries, including at UN headquarters in New York in 2001, and has never run into problems, said artist Sandra Bromley, who built the sculpture with Wallis Kendal.
Besides the weapons, the exhibit includes panels with photographs of more than 100 victims of violence from dozens of countries, including two images of Tibetan nuns.
"The message is the unmasking of violence, we wanted to challenge the culture of violence and create dialogue about it," she said.
"This is on public display to the world and China wouldn't stand for that at a UN facility," said Knight, adding he's surprised UN staff gave in to China's pressure. It's ironic that a sculpture promoting peace would be censored at the UN, an organization devoted to peace and security, he said.
Kendal and Bromley's sculpture was displayed first at the Edmonton Art Gallery in 2000.