The event will see about 200 art displays staged in dozens of venues around the city until September 15.

Former prime minister Malcolm Fraser, patron of the exhibition, officially opened the biennale tonight.

"I think Ballarat is very lucky to have people who have put this exhibition together," he said at an event at the Art Gallery of Ballarat.

"It's wonderful for Ballarat. It's wonderful for the photographers who can have their work shown off in this environment, with the number of people who'll come here.

"I hope those who've come from far places will go home and say exhibiting in Ballarat was well worth doing and a lot of people saw my photographs."

Mr Fraser said the rise of digital photography had become an "extraordinary weapon" in the hands of amateurs like himself, but admitted he occasionally struggled with the technology.

"I have my own printer, and I've learned enough about Adobe that probably I can understand one half of one per cent of it," he said.

"If I need to do something then there's somebody down the road, I can say 'I've forgotten how to do this' or 'I want to do something I haven't done before' and he'll come up and tell me what buttons to push."

Festival director Jeff Moorfoot welcomed the biennale's international participants and said some of the art on display could prove controversial.

"The whole purpose of this festival is to present the diversity of photography," he said.

"Out of 200 exhibitions we have maybe five or six that some people may be offended by. I don't have an issue with people being offended by photography.

"We are a festival of art, not a festival of décor."