The bankruptcy restructurings of General Motors Corp and Chrysler LLC have improved credit market access for auto suppliers, but the sector is far from healthy and requires close government monitoring, an Obama administration official said on Tuesday.

Ron Bloom, a leader of the administration's autos task force, also told a House of Representatives hearing that the task force has ended the government-backed consumer warranty program for GM (GM.UL) and Chrysler (CCMLPC.UL) and returned $641 million of funds from that initiative to the Treasury.

"With the successful emergence of the new companies, consumers can now feel assured that the companies have the financial wherewithal to meet their warranty commitments on a continuing basis," Bloom told a Judiciary subcommittee.