The interactive parts of the exhibition were designed to encourage collaboration between people, linked to a central theme of world peace, she said.
The mixed-media presentation, Ono's first solo show in Australia, features works from more than five decades including sculptures, vintage collage spreads and a chess game with all-white pieces.
"Change is not that easy but we have to understand that if we don't allow change, that is death," Ono said.
A prolific user of Twitter, Ono tweeted against gun violence this year and posted a photograph of the blood-stained glasses that apparently were worn by Lennon when he was shot to death in New York in December 1980.
"When John and I stood up, very few people were activists. Now I think 90 percent of the world is activists," she said. "If you're not an activist, you'd be considered a nerd maybe."