UNESCO is worried about the possibility of the state government in Queensland allowing exports of uranium across the Great Barrier Reef.
The Ben Lomond Uranium mine, west of Townsville, is currently dormant, but the state government is lifting a ban on uranium mining.
Mega Uranium, which owns the mine, is looking at the best method of extraction.
Queensland Mines Minister Andrew Cripps said a case would have to be made to have a licensed port off the east coast, and he has not ruled out Townsville.
The ABC reports Adelaide and Darwin are the only licensed uranium ports now.
Tim Badman from the International Union for Conservation of Nature, which advises the UN's world heritage committee, has told the ABC this would be a "new threat to the Great Barrier Reef".
UNESCO is considering if it will place the reef on the "in danger" list.
It will meet in June and says the potential export of uranium through the reef must now be considered in that response.