Jobs at Opel's three factories in Eisenach, Kaiserslautern and Russelsheim will be protected until 2018 under a new agreement signed with the unions last week.

"For the company and its employees this is an important step toward securing our future," Ulrich Schumacher, Opel's head of personnel said in a statement.

The three factories employ around 7,150 staff.

The deal follows a visit to Germany last week by GM's new chief executive Mary Barra and is seen as a sign of the determination to turn round the struggling unit, which has lost some US$18bn over the last 12 years. GM has previously stated that it expects Opel to return to profitability by 2015.

As part of the deal, Opel has said it will build an additional model at Russelsheim, continue to make Corsa and Adam models in Eisenach while component production will continue at Kaiserslautern.

A new Corsa model will be launched later this year followed by a new Astra early in 2015. The new Astra will also be built at the Ellesmere Port plant in the UK run by sister company Vauxhall.