General Motors revealed it had clocked up nearly $US180 billion in debt as it filed for bankruptcy protection in the US with a government-backed plan to create a 21st-century company that can compete in world markets.

“GM’s and its stakeholders have achieved a viable, achievable plan that will give this iconic American company a chance to rise again,” US President Barack Obama said when announcing the move.

He farewelled the “old GM” and welcomed the “new GM,” saying the government was becoming a “reluctant” owner. His goal was a short receivership and the government, which becomes a majority owner, will “take a hands-off approach and get out quickly.”

In Australia, Dow Jones reported GM Holden chief executive Mark Reuss as saying the business was "safe", with no job losses planned for now.

Mr Reuss said Holden was well placed as one of GM's three vital subsidiaries in the Asia Pacific region and that the bankruptcy would not affect the Australian unit's access to capital.

"We are a viable, sustainable business in the long term," he said. "We are cashflow positive, we are liquid [and] on the verge of turning a profit here this last month even in a down business."

Mr Reuss said Holden had moved quickly to respond to the downturn, cutting shifts and freezing pay, and was well placed with the best selling Commodore and the new compact Cruze on the way.

"With all those things in place, with the right operating and structural cost, we can be very profitable here," he said.

Holden had no plans to cut jobs at this stage and the company did not have debts owing to its parent, Mr Reuss said.

In the US, GM reported $US82.3 billion in assets and $US172.8 billion in debt. The US government will bankroll the transformation of the 100-year-old automaker, a victim of tumbling sales and higher fuel prices.

Until last year, when toppled by Toyota, it was the world’s leading car maker for 77 years.

The US plans to convert much of its $US50 billion of loans to a 60% stake in the new entity. The bankruptcys filing in New York coincided with a deadline for GM to convince a government auto task force that it could reorganise out of court through debt and cost-cutting.

GM is the largest manufacturer to file for bankruptcy, surpassing Chrysler.

Detroit-based GM plans to launch a new company in 60 to 90 days, armed with vehicles from its Cadillac, Chevrolet, Buick and GMC units for the US market.

The court will supervise the sale or liquidation of unprofitable brands, such as Saturn and Hummer, and at least 11 unwanted factories.

A GM statement shows consolidated debt in the new company of $US17 billion, excluding liabilities such as a workers’ healthcare trust, down from $US54.4 billion in March. The filing put the new-entity loan total from the US and Canadian government at as much as $65 billion.

Aside from the US government’s equity share, GM’s statement calls for a worker health-care fund to get a 17.5% stake and the Canadian governments to take 11.7%. Bondholders would be eligible for 10% and warrants to buy another 15%.

In separate move, the German government will provide €1.5 billion in interim loans to a Canadian-Russian consortium to take control of GM’s European divisions, Opel and Vauxhall.

Magna International, a Canadian car-parts maker, has the backing of Russian carmaker GAZ and Servbank.