General Motors and Chrysler were close to securing a $15bn (£10bn) bail-out from Washington last night as the White House and Congressional leaders prepared to appoint a "car tsar".

Legislation to spare GM and Chrysler from bankruptcy could be unveiled today. It is understood that loans will be granted to the Detroit-based manufacturers as a stopgap measure until January, when Barack Obama assumes the presidency and Congress reconvenes.

"There is a lot of work going on behind the scenes," said a source familiar with the talks. "There will be a single person to oversee this initiative. This legislation is an interim measure to prevent collapse so that the new president and new Congress can determine a longer term plan."

However, it was reported yesterday that the White House and Democratic leaders in Congress were at odds over when the tsar should be appointed. The Bush administration is believed to favour an immediate appointment but Congress prefers to leave the responsibility to Obama's team.

It is understood that the funding for GM and Chrysler will come from a $25bn energy department fund for developing fuel-efficient vehicles.

The manufacturers appear to have won a short-term reprieve amid fears that the collapse of GM or Chrysler could ravage an already reduced US jobs market.

The strain facing the motor industry was further apparent this weekend when one of Britain's largest car-parts groups, Wagon Automotive, teetered on the brink of collapse, endangering 4,500 jobs across Europe. The company, which employs 500 in Britain at plants in Walsall and Coventry and a Birmingham head office, is expected to call in administrators within days.

Wagon's carmaker clients and its American backer, Wilbur Ross, had agreed to pump tens of millions of euros into the company, but the banks refused to play their part to keep the business afloat. The White House, which has veto powers, has opposed bailing out Detroit from the $700bn Troubled Asset Relief Program but it signalled over the weekend that a deal could be reached. House speaker Nancy Pelosi had refused to draw the bail-out cash from the $25bn energy department fund but, according to reports, she relented over the weekend.

A spokeswoman for the Bush administration said "constructive discussions" had been held with Congress members.

"We hope to make progress toward assistance for the automakers," she said, adding that there must be a guarantee that the money would be repaid.

Chrysler said yesterday that it was "encouraged by the discussions as it appears we are making progress". General Motors declined to comment and Ford did not return calls.

Obama backed a Detroit bail-out yesterday as he ruled out letting the motor industry collapse - but warned that it must undergo a comprehensive restructuring.

"I don't think it is an option to simply allow it to collapse," Obama said in an interview on NBC. "What we have to do is to provide them with assistance but that assistance is conditional on them making significant adjustments. They are going to have to restructure and all of their stakeholders are going to have to restructure."

In his weekly address to the nation, via radio and YouTube, Obama gave details of the stimulus package that has become his priority after he takes office. The plan, which economists have argued should pump $700bn into the economy, will be the largest public construction programme since the 1950s, when work began on the interstate motorway network, Obama said.

As well as building roads and repairing bridges, the 2.5 million jobs created by the programme will encompass the middle classes with investment targeted at technology and the environment. "It is unacceptable that the United States ranks 15th in the world in broadband adoption. Here, in the country that invented the internet, every child should have the chance to get online," Obama said.