Anti-coal protest disrupts Sydney bank

A normally busy Commonwealth Bank branch in the heart of Sydney was brought to a standstill when environmental activists staged a protest inside.

About a dozen anti-mining protesters staged a sit-in at the bank's George St branch on Thursday morning, protesting the bank's financing of a new coal mine in Queensland's Galilee Basin.

The activists, who fear the mine will damage the Great Barrier Reef, linked themselves in a circle on the branch floor and handed out leaflets to passers-by on the street, winding up the protest about 1pm.

"We're encouraging customers of the Commonwealth Bank to take their investments out of the bank if they don't give a guarantee not to continue enormous investment and loans into dirty fossil fuels," said Phil Bradley, a representative of the grassroots group.

Police were on the scene and spoke to the protesters, but did not attempt to remove them.

"I think they have a right to do it ... I'll think about it," one Commonwealth Bank customer told AAP upon leaving the building.

The action is part of a week of environmental activism targeting the bank for its continued investment in fossil fuels.

The Sydney protest followed a marathon effort in Melbourne on Wednesday, when protesters camped inside a bank branch for nine hours.

A Commonwealth Bank spokesperson said the protesters had a right to express their views peacefully and that the bank had invested in more than 170 renewable energy projects globally.