WASHINGTON - IMPERILED automakers and their union worked feverishly on Wednesday to sell a skeptical Congress on a US$34 billion (S$51.87 billion) aid plan, promising labour concessions and industrial restructuring.

One day before the chiefs of the auto companies return to Capitol Hill to make their urgent cases for loans, Democratic Senator Harry Reid said the money was unlikely to come from the Wall Street rescue fund.

'I just don't think we have the votes to do that now,' Mr Reid told wires agencies in an interview.

The White House called the timing of his comments 'interesting,' coming on the eve of high-stakes congressional hearings Democrats demanded.

'It's not hospitable,' said Ms Dana Perino, the White House press secretary.

In congressional meetings, industry officials said the collapse of one or more of the major carmakers could greatly worsen the nation's recession and undermine the companies' ability to survive.

'We're on the brink with the US auto manufacturing industry.

We're down to months left,' Chrysler's vice-chairman, Mr Jim Press, told newswires in a separate interview.

'If we have a catastrophic failure of one of these car companies, in this tender environment for the economy, it's a huge blow. It could trigger a depression.'

The United Auto Workers union, scrambling to preserve jobs and benefits, agreed at an emergency meeting in Detroit, Michigan, the centre of the auto industry, to allow the companies to delay payments to a multibillion-dollar, union-run health care trust and to scale back a jobs bank in which laid-off workers are paid most of their wages.

The concessions could help mollify some lawmakers who have criticised the union's benefits as too rich when compared with those of workers at foreign-brand auto plants in the United States.

The Bush administration and auto-state Republicans and Democrats are pushing to help the automakers with aid from a different source: a previously approved US$25 billion programme that was passed to help them produce more environmentally advanced vehicles.

Environmentalists, and a number of their powerful friends in Congress, are opposing that idea vigorously.

Mr Reid, who as majority leader controls the Senate's agenda, said the administration could act unilaterally to use a portion of the Wall Street bailout programme for loans to the automakers, but the White House has resisted that approach consistently.

'There's talk going around now that the Bush White House may ask for' the second US$350 billion installment of the US$700 billion financial industry rescue fund, Mr Reid said.

But if Mr Bush's team does not act, he said, 'I think that we are probably going to have to try to do something' in Congress.

Mr Reid said he would rely on Democratic Senator Chris Dodd, the Banking Committee chairman, to determine what kind of legislation would be appropriate.

The autoworkers' concessions are 'a step in the right direction,' Mr Reid said.

'I think it's too bad that negotiated contracts between labour and management are going to have to be changed. But it's obvious to everyone - as strong of a union guy as I am - it's obvious that there has to be some changes made,' Mr Reid said.

Ahead of Thursday's televised hearings, GM's president and chief operating officer, Mr Fritz Henderson, met with congressional aides and said bankruptcy for his company would further erode consumer confidence.

About 25 auto dealers also combed through House and Senate office buildings, lobbying for the bailout package.

General Motors, Chrysler LLC and Ford Motor submitted three separate survival plans to Congress this week after flunking their first attempt to persuade lawmakers to throw them a lifeline.

GM and Chrysler said they needed an immediate infusion of government cash to last until New Year's, and both said they could drag the entire industry down if they should fail. Ford wants a US$9 billion 'standby line of credit' in case a competitor fails.

Chrysler said it needed US$7 billion by year's end to keep operating. GM asked for an immediate US$4 billion as the first installment of a US$12 billion loan, plus a US$6 billion line of credit to use if conditions worsen.

Ford's chief executive, Mr Alan Mulally, and GM's chief executive, Mr Rick Wagoner, said they would work for US$1 a year if each company accepted government loans.

The carmakers also have offered to cancel bonuses and merit raises. Chrysler said its chief executive already has cut his annual pay to US$1.

All three plans envision the government getting a stake in the companies that would allow taxpayers to share in future gains if they should recover.

The Senate Banking, Housing and Urban Affairs Committee was to hear testimony on Thursday from the executives, the UAW's president, Mr Ron Gettelfinger, and the head of the Government Accountability Office on the companies' plans. The House Financial Services Committee planned a similar session Friday.

Officials at the White House and the Treasury and Commerce departments were scouring the plans. White House press secretary Dana Perino said it was 'too early to say' whether the companies have outlined a path toward viability that justifies new federal assistance.

President-elect Barack Obama said it appeared that Big Three chiefs were returning to Washington with a 'more serious set of plans'.

The bailout faces a sceptical public. Sixty-one percent oppose providing the auto companies with billions in federal assistance, according to a CNN-Opinion Research Corp poll released on Wednesday.

Fifty-three per cent said it would not help the economy.

Few saw any quick impact if the US auto industry were to go bankrupt - only one in three said it would affect them immediately or in a year.

Most of the rest said they thought it would affect them eventually, though nearly one-quarter said they would never feel its impact. -- AP