William McAleer, who formerly ran General Motors's corporate quality audit, wrote to GM's board about serious safety flaws in vehicles more than 11 years before the automaker recalled millions of vehicles for ignition switch faults linked to at least 13 deaths.

McAleer has given a copy of his 2002 letter, addressed to the then GM directors, along with copies of postal delivery receipts, to Reuters.

Pursued by the news agency, GM spokesman Jim Cain said: "We are conducting what we believe is the most exhaustive and comprehensive safety review in the history of the company, and that includes looking at vehicles that were built in the late 1990s. And if we find anything that is a safety issue, we will act."

McAleer, earlier in the month, sent copies of the 2002 document to members of the US House and Senate committees that are probing the Detroit-based firm and its handling of the ignition switch problem and related vehicle recalls.

McAleer's letter accused GM's top quality executive in North America at the time, Tom LaSorda, of a "stonewall" that included trying to prevent McAleer from getting in touch with higher management.

LaSorda, who was then a GM vice-president, became CEO of Chrysler and later CEO of Fisker Automotive. He now works as a venture capitalist at Michigan, US-based IncWell.

GM has recalled over 20 million vehicles this year, mostly in the US. Close to 6.5 million of these were recalled because of defective ignition switches.

The automaker has fired 15 employees and has taken disciplinary action against five others for their roles in the bungled handling of the ignition-switch issue and related recalls, GM CEO Mary Barra said on 6 June.