Adani Mining has asked its four engineering contractors working on the Carmichael project to halt work around the mine, the Guardian Australia reported, citing sources familiar with the matter.
Halting work at this stage of the project makes no sense even as a savings measure, and raises speculation that the company might scrap the project altogether, Guardian Australia said.
Adani has signed up buyers for about 70% of the 40 million tonnes coal the Carmichael project is due to produce in its first phase, with production expected to begin in late 2017.
Guardian Australia said it is understood that about 40 engineers working for one of Adani's contractors, WorleyParsons, were among those pulled off the project.
Tim Buckley, a director of energy finance studies, Australasia, at the Institute for Energy Economics and Financial Analysis, which opposes new coal developments said halting work at this stage "just crucifies the project", the newspaper reported.
SMEC, one of the contractors hired by Adani, declined to comment.
Adani and its other contractors Aecon, Aurecon and WorleyParsons could not be reached for comment outside regular business hours.
Adani's ambitions in Australia have been uncertain following a surprise election result in Australia's coal-rich Queensland state, leading to a policy reversal, and heightened pressure to protect the Great Barrier Reef, the world's largest coral reef ecosystem.