General Motors is reviewing its European operations as it aims to trim costs in the loss-making division.
General Motors is suffering from weaker sales
The US car maker said production could be reduced but dismissed reports it had already decided to cut 3,000 jobs.
Earlier this year, GM merged its three European car making businesses - Opel, Vauxhall and Saab - under a single regional chairman, based in Zurich.
It suffered a third consecutive month of lower sales in August as its cars lost out to competitors' newer models.
The world's biggest car maker said the restructuring could lead to a cut in production levels at plants producing new models.
"We are in the middle of a two-month review," a spokeswoman for General Motors Europe told BBC News Online. "But there will be no decision before November."
GM's losses in Europe have totalled almost $2bn
(£1.1bn, 1.6bn euros) over the past four years.
The firm employs about 63,000 people in 11 factories across the UK, Belgium, Germany, Poland, Portugal, Russia, Spain, and Sweden.
GM is not the only car maker facing an increasingly competitive European market.
Ford is ending production at Jaguar's plant in Coventry in the UK as it tries to stem losses at its luxury brands subsidiary and VW has warned of job cuts at its German plants unless staff accept a two-year pay freeze.