Thousands of protesters clad in stop sign red have turned out across the country to call on the Queensland and Commonwealth governments to halt the proposed Adani mega mine.
Major rallies were held at Bondi Beach, Port Douglas and Carlton North, with dozens of other events held across each state and territory on Saturday.
Many organised themselves into human signs to spell out "Stop Adani" as part of the national day of action, which coincided with new polling that shows more than half of Australians oppose the central Queensland mine.
Two-thirds of people also believe the Queensland government should veto a proposed $1 billion Commonwealth loan for a rail line to the Carmichael mine.
In Canberra, hundreds of demonstrators gathered outside Parliament House, waving placards and chanting slogans before heading off on a march.
"The mine is just going to ruin everything - the water, the reef, the farming land - and also we're lending them $1 billion and I cannot believe we can't spend that money on jobs in other areas like renewables," Michele Smith told AAP.
Fellow protester Kathy Kituai was sceptical about what the state and federal governments stand to gain from the "insane" project, while Lois McRae said she was worried about the irreversible damage it may cause.
Meanwhile in Brisbane, Sea Shepherd Australia's Jeff Hansen said "huge numbers" of coal ships would move through the Great Barrier Reef if the mine goes ahead, posing a serious threat to the whales' birthing grounds.
Almost 2200 respondents quizzed in the recent Reachtel poll were told Adani wanted to build a new coal mine in Queensland, which the Indian company said would create local jobs.
They were also told concerns had been raised about the company's corporate track record and the environmental impact of the mine, before being asked if they supported or opposed the project going ahead.
A majority of people (55.5 per cent) either opposed or strongly opposed the mine, while 26.1 per cent said they supported or strongly supported it. Almost one in five (18.4 per cent) were undecided.
An ABC Four Corners investigation this week aired allegations of bribery, corruption, tax evasion and money laundering by Adani-linked companies.
Those polled were also told Queensland Premier Annastacia Palaszczuk made an election commitment that Labor would not spend public funds on Adani's private rail line for their coal mine.
People were then asked if the Queensland government should keep its promise and use its power to veto a $1 billion Commonwealth loan to Adani for the rail line.
Two-thirds of respondents (65.8 per cent) said they should veto the loan, while 17.7 per cent said they should not, with 16.5 per cent undecided.
Asked about the large-scale activism on Saturday, Ms Palaszczuk said the mine was subject to tough environmental conditions.
The Stop Adani Alliance, which is organising the national rallies, is made up of 31 organisations.