Almost a third of the world's protected lands face intense pressure from humans with even rich nations such as Australia failing to conserve key biodiversity, a new study by Australian scientists has found.

The research, published in Science on Friday, found that while declared protected zones had quadrupled in size in the past quarter century, much of that land enjoyed little protection from farming, logging or other human intervention.

“One third of that land is in a terrible state, doing nothing for biodiversity conservation," said James Watson, interim director of the University of Queensland's Centre for Biodiversity and Conservation Science and an author of the report.

"Nations across the world are exaggerating in an incredible way their contribution to solving the biodiversity crisis.”