Conservationists warn toxic canisters found washed up on Queensland beaches could be deadly to marine life on the Great Barrier Reef.
The containers of deadly aluminium phosphide have been found on five central Queensland beaches, as well as other parts of the coast between Torres Strait and the Gold Coast.
The Australian Maritime Safety Authority is investigating.
Capricorn Conservation Council spokesman Michael McCabe says the deadly chemicals are likely to have been dumped from passing ships.
"Roughly half of the stuff turning up on our beaches comes from somewhere in the Pacific or off nearby ships," he said.
"We've had recent incidents of ships dumping illegally off Gladstone.
"We may see a massive increase in shipping if all these approvals go ahead.
"Unless something that can be done to stop the accidental or deliberate dumping of such toxic waste, we've got real problems."
Mr McCabe is calling for shipping bans for any operators caught dumping rubbish into the Great Barrier Reef.
"They should be able to identify from batch numbers I guess who's responsible," he said.
"We'd like to see very severe penalties.
"We've asked in the past for any company who breaches maritime rules on the Great Barrier Reef be given a ban, as you would if you're an illegal driver.
"Some of the fines which we handed out are paltry - there needs to be absolute deterrent for these events every occurring again."
He says there could be serious environmental damage if the chemicals leak out.
"It is highly toxic to all living life and it would depend on how much was released," he said.
"It's likely I think to be devastating to anything in the near area, obviously depending on how much is released and how much is diluted.
"All these things add to the accumulation of toxins and risks to any person or animal that is exposed."