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

Ron Bloom, leader of the administration's autos task force, also told a House of Representatives hearing that the task force had ended the government-backed consumer warranty programme for GM and Chrysler and returned US$641m from that initiative to the Treasury, Reuters reported.

"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.

The report noted that lawmakers are mainly concerned about dealer closings and moves by GM and Chrysler in bankruptcy to shed massive potential liability claims from accident victims.

Legislation moving through Congress would require GM and Chrysler to address claims by dealers that their franchise rights were trampled in court.

Bloom said the task force was not involved in decisions by GM and Chrysler on individual dealers, but the administration strongly opposed any attempt to restore franchise agreements. He said it would "set a dangerous precedent" and would create new financial burdens for the companies.

"Political intervention of this nature could also jeopardise taxpayer returns by making it far more difficult for the companies to access private capital markets," Bloom said.

Parts suppliers received $5bn in government aid but the administration has said there is no near-term plan to extend more assistance.

At least 15 auto parts suppliers have filed for bankruptcy or had their assets seized by creditors in 2009, according to the Motor & Equipment Manufacturers Association.

Bloom said GM and Chrysler's restructuring had reduced uncertainty about their finances for now, creating a "modest opening" in credit markets for suppliers.

"Nonetheless, the task force is mindful of the continuing challenges facing auto suppliers and is continuing to actively monitor the health and state of the supply base during this period," Bloom added.