The US government announced a series of investigations into "unintended acceleration" in Toyota and other brands of cars on Tuesday, and said NASA engineers would be called in to help.

In a statement, Transportation Secretary Ray LaHood said US space agency experts in "electromagnetic interference," computer-controlled electronic systems and software integrity would be enlisted to help the high-profile probe.

It comes after a series of mass recalls has rocked confidence in the auto sector, which was already battered by low consumer spending amid the global economic crisis.

Toyota has been at the center of that maelstrom after recalling more than eight million vehicles worldwide.

Toyota has blamed the problems on a mechanical defects including a sticking accelerator pedal, but has faced allegations it is in fact due to an electronic failure.

"We are determined to get to the bottom of unintended acceleration," said LaHood. "For the safety of the American driving public, we must do everything possible to understand what is happening. And that is why we are tapping the best minds around."

LaHood also announced a sector-wide investigation by the National Academy of Sciences, covering electronic vehicle controls in all manufacturers' vehicles.

That probe is expected to last 15 months.

The Department of Transportation plans to buy cars that are suspected of unintended acceleration and subject them to a battery of tests.

LaHood, facing criticism that the US government failed in its duty to protect consumers, also announced an investigation to see if early complaints were ignored, or not properly dealt with.

It will see whether the National Highway Traffic Safety Administration (NHTSA) "conducted an adequate review of complaints of alleged unintended acceleration reported to NHTSA from 2002 to the present."