Labor has rejected government claims the Adani Carmichael coal mine project in central Queensland deserves a $900 million concessional loan funded by taxpayers, saying the project should stand or fall "on its own two feet".
The opposition supports the $22 billion endeavour, which backers say will create thousands of jobs, but resources and northern Australia spokesman Jason Clare has dismissed Deputy Prime Minister Barnaby Joyce's claim on Tuesday the government funding is a "tipping point issue to get this mine going".
"The project should stand on its own two feet," Mr Clare told ABC Radio on Wednesday morning.
The government is currently considering offering a $900 million loan to the company, to build a railway that would transport coal from the mine to the port at Abbot Point, where it would be shipped to India.
While Adani says the loan would help fund the project's 389 kilometre rail line, the Indian energy giant has said it is "not critical" or "make or break".
"On that basis alone ... it doesn't meet the requirement of the Northern Australia Infrastructure Fund," Mr Clare said.
"The government's all over the shop on this. Malcolm Turnbull's in India saying that this should be done independently by the board ... Barnaby [Joyce] yesterday was basically directing the board to fund this project."
In October 2015, then-resources minister Josh Frydenberg said it wouldn't be a priority project for federal assistance.
"This is a commercial operation, it needs to stand on its own two feet," he said.
Opposition Leader Bill Shorten said on Wednesday he hoped the mine became a reality.
"I want to see more jobs in Australia, I want to see more jobs in regional Queensland, but it has got to stack up commercially, it has got to stack up environmentally," he said. "But I can't for the life of me see any good reason why Australian taxpayers should be underwriting a billion-dollar loan to a giant billionaire Indian mining company."
"The issue needs to be fixed and will be fixed," Mr Turnbull said.
The project is facing widespread opposition from conservationists concerned about the "carbon bomb" impacts on global greenhouse gas emissions as well as local environmental impacts on the Great Barrier Reef.
Supporters tout the creation of thousands of direct and indirect jobs in a region plagued by high unemployment.
The ongoing uncertainty over the project comes as a new report warns climate change-related damage to the Great Barrier Reef could see one million visitors a year abandon the reef, costing the local economy $1 billion and 10,000 jobs.
Overall, the loss of coral reefs could cost the global economy $1 trillion, the not-for-profit group says, citing recent research.
"The GBR is not the only reef affected by unprecedented coral bleaching in recent times. The longest global bleaching event on record began in 2014 due to record breaking ocean temperatures and continues into 2017," the report states.
"The burning of coal, oil, and gas is putting Australia's iconic reefs at risk of further bleaching and death. The rate of surface ocean warming in the 21st century is seven times faster than during the 20th century and the frequency of extreme sea surface temperature events has increased...
"Extreme coral bleaching and the death of reefs will become the new normal unless serious and rapid reductions in greenhouse gas emissions are achieved."
According to new legal advice for the Australian Conservation Foundation, the company directors of the NAIF could be in breach of their duties and face legal action if they approve the loan for the Carmichael project.
Lawyers for Environmental Justice Australia found that, under the Public Governance, Performance and Accountability Act 2013, the financial risks associated with climate change must be considered in the decision.
"NAIF must consider climate risks. These are assets that will be useless within a decade," ACF president Geoff Cousins said.
"Investment in coal infrastructure risks public money and in the meantime helps to drive dangerous global warming. NAIF directors who support it should be held accountable."