General Motors and its auditor, Deloitte & Touche, have expressed doubts over the automaker's ability to survive, which in part will depend on car sales rising next year. The embattled automaker made the disclosure in a 480-page filing with the US Securities & Exchange Commission (SEC).

GM has sustained large and continuing losses, while saying it needs additional federal loans to remain in business. Thursday's statement from the company's auditors presents another hurdle the automaker will have to clear as it makes the case that it deserve additional taxpayer support going forward.

The Obama administration, under the terms of the $13.4 billion in federal loans GM has already requested, must determine that the company's plans make it viable in the long run. The government must determine that GM has a "positive net present value" or else demand repayment of the loans within 30 days - a development that would almost certainly plunge the company into bankruptcy and quite possibly force it out of business.

But the government has wide latitude in how it judges the company's net present value, based on assumptions it makes about future sales, car prices and costs for the company going forward. The administration clearly does not want to force the largest US automaker into bankruptcy.

The GM filing disclosed that the Treasury already agreed to waive requirements that the automaker meet certain terms of the original loan agreement, including that it win agreement with creditors to convert two-thirds of its unsecured debt to equity by 17 February.

Privately held Chrysler does not have to file a year-end financial statement with the SEC. Last week, Ford Motor said its auditors have not substantial doubt about its future. Ford went into this auto crisis with a much stronger cash position than GM or Chrysler.

Vehicle sales, which have dropped 40 per cent in the US from their peak, need to recover next year under the plan submitted to Congress. GM's survival also depends on its ability to obtain liquidity and financing to establish an appropriate level of debt, cut costs and have consumers convinced of its viability - as well as partly-owned GMAC's ability to obtain funding from both wholesale and retail financing.

Deloitte & Touche made a similar analysis: "The Corporation's recurring losses from operations, stockholders' deficit and inability to generate sufficient cash flow to meet its obligations and sustain its operations raise substantial doubt about its ability to continue as a going concern."

"The failure to obtain sufficient funding from the US government or governments outside the United States may require us to shrink or terminate operations or seek reorganization for certain subsidiaries outside the United States," the filing said. "If we fail to obtain sufficient funding for any reason, we would not be able to continue as a going concern and could potentially be forced to seek relief under the US Bankruptcy Code.''

GM's stock was 18 per cent lower in pre-market trading.