The Senate has passed a motion asking Environment Minister Greg Hunt to reverse a decision to allow a coal port expansion near the Great Barrier Reef.

The Senate has passed a motion calling for the reversal of a coal port terminal expansion approval allowing dredge dumping in the Great Barrier Reef Marine Park.

Greens senator Larissa Waters, a Queenslander, moved the motion on Monday calling on federal Environment Minister Greg Hunt to revoke the government’s approval of the Abbot Point coal port extension.

In January, the Great Barrier Reef Marine Park Authority (GBRMPA) approved a proposal from the North Queensland Bulk Ports Corporation to dump three million cubic metres of dredge spoil in the marine park over several years.

Mr Hunt had earlier given approval to the dredging in Queensland’s north, which will turn Abbot Point into one of the world’s largest coal terminals.

But Senator Waters argued that new documents, obtained by Greenpeace, showed that GBRMPA had initially wanted to reject that plan to dump dredge spoil on a sand bed in the marine park, 25km from the port and 20km from the nearest coral reef.

“The Senate and the community are sending a strong message to the Abbott Government that dumping millions of tonnes of sludge in the Great Barrier Reef is unacceptable,” Senator Waters, the Greens’ environment spokeswoman, said.

“Minister Hunt has been telling us that the damage from the Abbot Point dumping can be offset but documents released under freedom of information this week show that’s simply not the case.

“The documents show the Great Barrier Reef Marine Park Authority found that it would be impossible to offset the damage because it was too great.”

On Tuesday, Senator Waters’ motion passed on the voices with support from Labor and the Greens.

GBRMPA chairman Russell Reichelt this week said the documents cited by Greenpeace were “preliminary working drafts which were never submitted” to the authority’s senior management, with that draft assessment occurring before strict conditions were imposed on the dumping.