The sails of the Sydney Opera House were lit up in all the colors of the psychedelic rainbow on Friday as the city switched on the lights for the Vivid Sydney light festival.

Hypnotic images inspired by Australian native plants were projected onto the World Heritage listed building, alongside more than 50 other light installations and projections around the harbor.

"It's so beautiful. I had no idea they could project the colors so clearly and brightly like this," said spectator Mayo Matsuda, who is visiting from Kanagawa Prefecture in Japan.

(The Sydney Harbour Bridge)

As part of Vivid Sydney, which is Australia's largest event festival, the Sydney Harbor Bridge will host an illuminated disco-style dance floor at its summit for night-time climbers.

Vivid Sydney runs for 23 nights and includes musical performances, public talks and creativity workshops.

Last year, the Southern Hemisphere's largest light festival attracted 2.25 million visitors and injected over $172 million into the New South Wales state economy.