Climate protestors scale Sydney Opera House

Protesters have scaled Sydney Opera House and unfurled a banner on the iconic building urging world leaders to strike a treaty to combat climate change.

New South Wales state police said five people were taken into custody after coming down from the building this morning after clambering up it about two hours earlier.

Television footage showed several people with climbing harnesses and helmets clambering over one of the opera house's distinctive sail-shaped roof structures.

Broadcaster ABC reported the protesters attached a banner to the building that read: "Stop the Politics, Climate Treaty Now".