The Greens say expanding the Abbot Point port is economically crazy and environmentally negligent.
Queensland senator Larissa Waters says the federal approval of one of the world's largest coal ports on the shores of the reef was ludicrous - especially considering Indian mining giant Adani's huge Carmichael project remains in doubt.
"(The port is) for a mine that doesn't have any finance, selling a product that the rest of the world doesn't want anymore," she said.
"This has got to be the craziest economic decision and the most negligent environmental decision that the Liberal government has made so far."
Federal Environment Minister Greg Hunt approved the Abbot Point project on Tuesday, with conditions including that no more than 1.1 million cubic metres of dredge material is removed.
The dredge material must also be placed in a designated onshore area.
It was the third version of the project to be submitted for approval and the material to be dredged is substantially lower than the 38 million cubic metres originally proposed.
The dredging area is more than 20km away from any coral reef complex.
But Senator Waters warned dredging would also rip out seagrass meadows, which were turtle habitats, and clog inshore areas where coral spawned with spoil.
She said the time of coal and other fossil fuels had passed and the Commonwealth, and state government, should instead be focusing on renewables for future.
"I don't know what it's going to take for both levels of government to get global warming," she said.
"This is no joke folks, this is real, it's causing people an enormous amount of damage already, and it's coming to coastline near you."
Senator Waters believed Queensland's Labor government was equally complicit in the port because its name was on federal approval application forms.
Share
