* Follows worker rejection of Opel plant closure plan
* European car sales in freefall
* Chancellor Angela Merkel facing re-election in September
BERLIN, April 5 (Reuters) - The chief executive of General Motors and the head of its Opel unit in Germany will meet Chancellor Angela Merkel next week to discuss the rejection of a plant closure timetable by workers which could speed the factory's shutdown.
With job losses looming at Opel's Bochum plant and against a background of European car sales in freefall, government spokesman Georg Streiter said Dan Akerson and Karl-Thomas Neumann will have a one-hour session with Merkel in Berlin on Thursday.
Merkel is seeking a third term as chancellor in September. Her re-election in 2009 took place amid tortuous negotiations between GM and Berlin, which applied pressure to save Opel by selling a stake to supplier Magna.
The deal eventually fell through, but only after the election, which meant it did not spoil Merkel's victory.
Opel, GM's second-largest brand behind Chevrolet, has lost billions of euros in recent years as European car sales have plunged to near 20-year lows, despite repeated bouts of job cuts.
Opel workers at Bochum last month rejected a restructuring deal agreed by union leaders and management which would have kept the plant open through the end of 2016 on significantly reduced staff numbers.
The rejection could lead to the plant's closing at the end of next year.
Streiter said the meeting with Merkel coincided with a meeting of the GM board in Germany and was at the U.S. automaker's request.
Asked by reporters whether Opel would be the subject of Thursday's discussions, Streiter said he "could not rule it out".
German Economy Minister Philipp Roesler will not attend as he will be on an official trip to Turkey, his ministry said.
Management offered to keep the Bochum plant in western Germany open for another two years until the end of 2016 and then retain 1,200 of the more than 3,000 employees in other component and warehousing jobs.
In exchange, workers would have had to agree to wage increases being delayed.