The consortium, which has 29 members, was given £4m of funding by the Department for Environment, Food and Rural Affairs to help charities reduce their impact on the environment and tackle climate change.
Mark Walton, head of the consortium, said there was some good practice, but action was "patchy" and there was a lack of leadership and strategic thinking from charities.
"There is still a reluctance to address this," he said. "It's still seen as being on the fringe of things."
He said charities should take more practical steps to reduce their carbon footprints, such as cutting fuel usage, and set public targets that commit them to action.