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.