Nissan chief Carlos Ghosn has warned that the company's second-half profit will probably fall to zero as the global motor-industry crisis intensifies.

Earlier forecasts had been for a second-half net profit of 33.7 billion yen (£232.1 million). Ghosn, who is also Renault chief, said sales were diving in the US, and a strong yen was making its cars more expensive for foreigners.

Carmakers worldwide are warning they face disaster without taxpayer help. Britain's Society of Motor Manufacturers and Traders last night wrote to Alistair Darling requesting "a package of measures to stimulate demand", and today it emerged for the first time that Chinese manufacturers also need help.

Renault's earlier target margin of 6% will now come in at around 2.5%, Ghosn told the Wall Street Journal. His aim is to maintain a positive free cashflow, but he said the coming year would be a struggle.

"We have to recognise 2009 will be one of the most challenging years for our industry and the whole economy in the last 50 years," Ghosn said, backing the idea of government help in the form of low-cost loans to help carmakers retool to produce more-fuel-efficient vehicles.

Detroit's Big Three, General Motors, Ford and Chrysler, have visited Capitol Hill with their begging bowls. GM is seeking between $10 billion and $12 billion, Ford wants $8 billion and Chrysler $7 billion. GM chief Rick Wagoner told the Senate Banking Committee: "This is about much more than just Detroit. It's about saving the US economy from a catastrophic collapse."

The trio are looking for the government loans as they burn through cash. US sales are at "depression level", according to David Cole, chairman of the Center for Automotive Research in Ann Arbor, Michigan. Observers believe a deal in the final week of Congress is unlikely .

"Detroit's basic problem is that they created a business model that doesn't have a snowball's chance in hell of surviving in a global economy," said Republican Senator Lindsey Graham.