Auditor General Lyn Provost says she will not carry out an inquiry into what led Solid Energy to the brink of collapse this year.
Labour's State Owned Enterprises spokesman Clayton Cosgrove requested Ms Provost conduct the inquiry in the wake of revelations the coal mining company was almost $400 million in debt.
He claims poor oversight by ministers allowed Solid Energy's board and management to make series of poor decisions.
However Ms Provost said there were already a number of reviews under way about the company's performance and the monitoring of the Crown's investment in the company.
"The company is already subject to a significant amount of review, scrutiny, and change" Ms Provost said in a statement.
"Given these circumstances, it is my judgement that an Auditor-General's inquiry at the moment would not add enough value to justify the additional burden on the company and the taxpayer.
"I will reconsider my position if circumstances change to such an extent that proper public accountability is undermined."