The White House said it is "working around the clock" to address the auto sector's woes, as fresh doubts emerged over General Motors Corp.'s (GM) ability to survive without further help from the government.

"The administration is very mindful of the challenges in the auto sector," White House spokeswoman Jen Psaki said Thursday. "Our team is working around the clock to develop the most thoughtful approach possible to the situation."

Earlier Thursday, GM's auditors said its continuing losses, negative net worth and an inability to generate cash for continued operations across its global operations raise substantial doubt it can remain a going concern.

The warning was in GM's delayed 10-K filing with the Securities and Exchange Commission, and the statement forced GM to seek waivers from lenders.

House Speaker Nancy Pelosi said Thursday the decision whether to provide further financial assistance to the auto companies was up to the Obama administration.

But she said any assistance should be a "lifeline, not life support" and any decision to provide more taxpayer cash to the companies will be made only after it was determined they had a viable recovery plan.

-By Henry J. Pulizzi and Corey Boles, Dow Jones Newswires; 202-862-9256; henry.pulizzi@dowjones.com

(Bhattiprolu Murti and Sharon Terlep contributed to this report.)