Early-stage research into ways to limit the impact of climate change on the Great Barrier Reef is being approved in a "policy vacuum", potentially limiting risk assessments and undermining public support, researchers say.

So-called geoengineering to draw down carbon dioxide or mask the effect of a warming planet has begun to draw science funding, including for three projects to protect Australia's largest network of coral reefs.

Increasing cloud cover to help cool the Great Barrier Reef is one type of geoengineering being considered for testing. Credit:Photo: Bloomberg

However, "the current laws do not guarantee robust governance for field testing of these technologies," according to a paper published in the Climate Policy journal. "Nor do they provide the foundation for a more coherent national policy on climate intervention technologies more generally."

Of the three reef-related projects with feasibility study approval, two will start very small.