LONDON (AFP) - Britain's biggest trade union said it was keen to work with General Motors to ensure job cuts at its European division Opel were voluntary, after it announced 10,000 positions could go.

GM wants to slash costs by 30 percent at Opel, which would mean the elimination of about 10,000 jobs from a workforce of 55,000, GM vice president John Smith told European journalists during a telephone news conference.

The announcement comes a day after the US car maker stunned the auto sector by scrapping plans to sell the German-based unit.

"I have no doubt that whoever the owner would be, there will be major restructuring of GM operations," said Unite joint general secretary Tony Woodley.

"Inevitably some will go in the UK, but our task is to minimise the number of jobs lost and ensure that those who do go, go voluntarily.

"It is right that GM should hold onto its UK plants because this country is one of its strongest and most loyal customers," he added.

Carmaker Vauxhall is part of GM's European operation, with 5,500 workers mainly employed at car plants at Luton and Ellesmere Port, near Liverpool.

The government said earlier Wednesday that it wanted to hold talks with GM after it scrapped plans to sell Opel.